diff --git a/source/main/gfx/GfxActor.cpp b/source/main/gfx/GfxActor.cpp
index e491dc7fbf..fdcf14873a 100644
--- a/source/main/gfx/GfxActor.cpp
+++ b/source/main/gfx/GfxActor.cpp
@@ -2998,8 +2998,13 @@ void RoR::GfxActor::UpdateFlexbodies()
 
     for (FlexBody* fb: m_flexbodies)
     {
-        const int camera_mode = fb->getCameraMode();
-        if ((camera_mode == -2) || (camera_mode == m_simbuf.simbuf_cur_cinecam))
+        // Update visibility
+        fb->setVisible(
+            fb->getCameraMode() == CAMERA_MODE_ALWAYS_VISIBLE
+            || fb->getCameraMode() == m_simbuf.simbuf_cur_cinecam);
+
+        // Update visible on background thread
+        if (fb->isVisible())
         {
             auto func = std::function<void()>([fb]()
                 {
@@ -3008,10 +3013,6 @@ void RoR::GfxActor::UpdateFlexbodies()
             auto task_handle = App::GetThreadPool()->RunTask(func);
             m_flexbody_tasks.push_back(task_handle);
         }
-        else
-        {
-            fb->setVisible(false);
-        }
     }
 }
 
@@ -3039,7 +3040,10 @@ void RoR::GfxActor::FinishFlexbodyTasks()
     }
     for (FlexBody* fb: m_flexbodies)
     {
-        fb->updateFlexbodyVertexBuffers();
+        if (fb->isVisible())
+        {
+            fb->updateFlexbodyVertexBuffers();
+        }
     }
 }
 
diff --git a/source/main/gui/panels/GUI_TopMenubar.cpp b/source/main/gui/panels/GUI_TopMenubar.cpp
index 858ad8b3ad..53a42cce90 100644
--- a/source/main/gui/panels/GUI_TopMenubar.cpp
+++ b/source/main/gui/panels/GUI_TopMenubar.cpp
@@ -1652,7 +1652,7 @@ void TopMenubar::Draw(float dt)
                         if (p.pp_beacon_type == 'L' || p.pp_beacon_type == 'R' || p.pp_beacon_type == 'w')
                         {
                             ImGui::SameLine();
-                            ImGui::TextDisabled("(!)");
+                            ImGui::TextDisabled("(special!)");
                             if (ImGui::IsItemHovered())
                             {
                                 ImGui::BeginTooltip();
@@ -1663,7 +1663,7 @@ void TopMenubar::Draw(float dt)
                         else if (p.pp_wheel_mesh_obj)
                         {
                             ImGui::SameLine();
-                            ImGui::TextDisabled("(!)");
+                            ImGui::TextDisabled("(special!)");
                             if (ImGui::IsItemHovered())
                             {
                                 ImGui::BeginTooltip();
diff --git a/source/main/physics/ActorSpawner.cpp b/source/main/physics/ActorSpawner.cpp
index 3f209a8181..7037923e3b 100644
--- a/source/main/physics/ActorSpawner.cpp
+++ b/source/main/physics/ActorSpawner.cpp
@@ -1496,7 +1496,7 @@ void ActorSpawner::ProcessFlexbody(RigDef::Flexbody& def)
     if (TuneupUtil::isFlexbodyRemoved(m_actor, flexbody_id))
     {
         // Create placeholder
-        m_actor->m_gfx_actor->m_flexbodies.emplace_back(new FlexBody(FlexBody::TUNING_PLACEHOLDER));
+        m_actor->m_gfx_actor->m_flexbodies.emplace_back(new FlexBody(FlexBody::TUNING_PLACEHOLDER, flexbody_id, def.mesh_name));
         return;
     }
 
@@ -1531,8 +1531,10 @@ void ActorSpawner::ProcessFlexbody(RigDef::Flexbody& def)
             this->GetNodeIndexOrThrow(def.reference_node),
             this->GetNodeIndexOrThrow(def.x_axis_node),
             this->GetNodeIndexOrThrow(def.y_axis_node),
-            TuneupUtil::getTweakedFlexbodyOffset(m_actor->getUsedTuneupEntry(), flexbody_id, def.offset),
-            TuneupUtil::getTweakedFlexbodyRotation(m_actor->getUsedTuneupEntry(), flexbody_id, def.rotation),
+            //TuneupUtil::getTweakedFlexbodyOffset(m_actor->getUsedTuneupEntry(), flexbody_id, def.offset),
+            //TuneupUtil::getTweakedFlexbodyRotation(m_actor->getUsedTuneupEntry(), flexbody_id, def.rotation),
+            def.offset,
+            def.rotation,
             node_indices,
             TuneupUtil::getTweakedFlexbodyMedia(m_actor->getUsedTuneupEntry(), flexbody_id, 0, def.mesh_name),
             TuneupUtil::getTweakedFlexbodyMediaRG(m_actor, flexbody_id, 0)
diff --git a/source/main/physics/ActorSpawner.h b/source/main/physics/ActorSpawner.h
index 517786dce7..f47733e40d 100644
--- a/source/main/physics/ActorSpawner.h
+++ b/source/main/physics/ActorSpawner.h
@@ -475,7 +475,7 @@ class ActorSpawner
     int                            m_first_wing_index;
     std::vector<CabTexcoord>       m_oldstyle_cab_texcoords;
     std::vector<CabSubmesh>        m_oldstyle_cab_submeshes;    
-    RigDef::Keyword                m_current_keyword; //!< For error reports
+    RigDef::Keyword                m_current_keyword = RigDef::Keyword::INVALID; //!< For error reports
     std::shared_ptr<RigDef::Document::Module> m_current_module; //!< For resolving addonparts
     std::map<Ogre::String, unsigned int> m_named_nodes;
     /// @}
diff --git a/source/main/physics/flex/FlexBody.cpp b/source/main/physics/flex/FlexBody.cpp
index a9802d1b92..9a62b6f85f 100644
--- a/source/main/physics/flex/FlexBody.cpp
+++ b/source/main/physics/flex/FlexBody.cpp
@@ -519,9 +519,11 @@ FlexBody::FlexBody(
     }
 }
 
-FlexBody::FlexBody(FlexBodyPlaceholder_t ticket)
+FlexBody::FlexBody(FlexBodyPlaceholder_t ticket, FlexbodyID_t id, const std::string& orig_meshname)
 {
     m_camera_mode = CAMERA_MODE_ALWAYS_HIDDEN;
+    m_id = id;
+    m_orig_mesh_name = orig_meshname;
 }
 
 FlexBody::~FlexBody()
@@ -554,6 +556,15 @@ FlexBody::~FlexBody()
     m_scene_entity = nullptr;
 }
 
+bool FlexBody::isVisible() const
+{
+    // Scene node is NULL if disabled via addonpart/tuneup.
+    return m_scene_node
+        && m_scene_node->isInSceneGraph()
+        && m_scene_node->getAttachedObject(0)->isVisible();
+        
+}
+
 void FlexBody::setVisible(bool visible)
 {
     if (m_scene_node)
@@ -608,6 +619,9 @@ void FlexBody::computeFlexbody()
 
 void FlexBody::updateFlexbodyVertexBuffers()
 {
+    if (!m_scene_node) // Disabled via addonpart/tuneup
+        return;
+
     Vector3 *ppt = m_dst_pos;
     Vector3 *npt = m_dst_normals;
     if (m_uses_shared_vertex_data)
@@ -679,19 +693,6 @@ void FlexBody::updateBlend() //so easy!
     }
 }
 
-std::string FlexBody::getOrigMeshName()
-{
-    std::string meshname = m_scene_entity->getMesh()->getName();
-    // Cut off the generated '_FlexBody_#@Actor_#' part
-    // TODO: fix the resource management to create resource group for each actor (currently done for each repo ZIP) - then we won't need those unique tokens anymore.
-    size_t pos = meshname.find("_FlexBody_");
-    if (pos != std::string::npos)
-    {
-        meshname = meshname.substr(0, pos);
-    }
-    return meshname;
-}
-
 int evalNodeDistance(NodeNum_t a, NodeNum_t b)
 {
     if (a > b)
diff --git a/source/main/physics/flex/FlexBody.h b/source/main/physics/flex/FlexBody.h
index 3f20508a0a..2e147c750d 100644
--- a/source/main/physics/flex/FlexBody.h
+++ b/source/main/physics/flex/FlexBody.h
@@ -61,7 +61,7 @@ class FlexBody
     typedef int FlexBodyPlaceholder_t;
     static const FlexBodyPlaceholder_t TUNING_PLACEHOLDER = -11;
 
-    FlexBody(FlexBodyPlaceholder_t);
+    FlexBody(FlexBodyPlaceholder_t, FlexbodyID_t id, const std::string& orig_meshname);
     ~FlexBody();
 
     void reset();
@@ -76,6 +76,7 @@ class FlexBody
     void computeFlexbody(); //!< Updates mesh deformation; works on CPU using local copy of vertex data.
     void updateFlexbodyVertexBuffers();
 
+    bool isVisible() const;
     void setVisible(bool visible);
 
     void setFlexbodyCastShadow(bool val);
@@ -84,7 +85,7 @@ class FlexBody
     Locator_t& getVertexLocator(int vert) { ROR_ASSERT((size_t)vert < m_vertex_count); return m_locators[vert]; }
     Ogre::Vector3 getVertexPos(int vert) { ROR_ASSERT((size_t)vert < m_vertex_count); return m_dst_pos[vert] + m_flexit_center; }
     Ogre::Entity* getEntity() { return m_scene_entity; }
-    std::string getOrigMeshName();
+    const std::string& getOrigMeshName() const { return m_orig_mesh_name; }
     std::vector<NodeNum_t>& getForsetNodes() { return m_forset_nodes; };
     std::string getOrigMeshInfo() { return m_orig_mesh_info; }
     std::string getLiveMeshInfo() { return RoR::PrintMeshInfo("Live", m_scene_entity->getMesh()); }
@@ -137,6 +138,7 @@ class FlexBody
     // Diagnostic data, not used for calculations
     std::vector<NodeNum_t> m_forset_nodes;
     std::string m_orig_mesh_info;
+    std::string m_orig_mesh_name;
 };
 
 /// @} // addtogroup Flex
diff --git a/source/main/physics/flex/FlexFactory.cpp b/source/main/physics/flex/FlexFactory.cpp
index e75764f090..19eecc5fb9 100644
--- a/source/main/physics/flex/FlexFactory.cpp
+++ b/source/main/physics/flex/FlexFactory.cpp
@@ -107,6 +107,7 @@ FlexBody* FlexFactory::CreateFlexBody(
         m_flexbody_cache.AddItemToSave(new_flexbody);
     }
     new_flexbody->m_id = flexbody_id;
+    new_flexbody->m_orig_mesh_name = common_mesh->getName();
     return new_flexbody;
 }
 
diff --git a/source/main/resources/CacheSystem.cpp b/source/main/resources/CacheSystem.cpp
index 59171ecdbf..c5028d8212 100644
--- a/source/main/resources/CacheSystem.cpp
+++ b/source/main/resources/CacheSystem.cpp
@@ -1740,6 +1740,9 @@ void CacheSystem::ModifyProject(ModifyProjectRequest* request)
         tuneup_entry->tuneup_def->use_addonparts.clear();
         tuneup_entry->tuneup_def->wheel_tweaks.clear();
         tuneup_entry->tuneup_def->node_tweaks.clear();
+        tuneup_entry->tuneup_def->protected_flexbodies.clear();
+        tuneup_entry->tuneup_def->protected_props.clear();
+        tuneup_entry->tuneup_def->protected_wheels.clear();
         break;
 
     default:
diff --git a/source/main/resources/addonpart_fileformat/AddonPartFileFormat.cpp b/source/main/resources/addonpart_fileformat/AddonPartFileFormat.cpp
index 2bdfee7d81..61de085449 100644
--- a/source/main/resources/addonpart_fileformat/AddonPartFileFormat.cpp
+++ b/source/main/resources/addonpart_fileformat/AddonPartFileFormat.cpp
@@ -137,6 +137,10 @@ void AddonPartUtility::ResolveUnwantedAndTweakedElements(TuneupDefPtr& tuneup, C
                     this->ProcessTweakWheel();
                 else if (m_context->getTokKeyword() == "addonpart_tweak_node")
                     this->ProcessTweakNode();
+                else if (m_context->getTokKeyword() == "addonpart_tweak_prop")
+                    this->ProcessTweakProp();
+                else if (m_context->getTokKeyword() == "addonpart_tweak_flexbody")
+                    this->ProcessTweakFlexbody();
             }
 
             m_context->seekNextLine();
@@ -332,7 +336,6 @@ void AddonPartUtility::ProcessTweakWheel()
 {
     ROR_ASSERT(m_context->getTokKeyword() == "addonpart_tweak_wheel"); // also asserts !EOF and TokenType::KEYWORD
 
-    // 'addonpart_tweak_wheel <wheel ID> <rim mesh> <tire radius> <rim radius>'
     if (m_context->isTokFloat(1) && m_context->isTokString(2))
     {
         const int wheel_id = (int)m_context->getTokFloat(1);
@@ -380,7 +383,6 @@ void AddonPartUtility::ProcessTweakNode()
 {
     ROR_ASSERT(m_context->getTokKeyword() == "addonpart_tweak_node"); // also asserts !EOF and TokenType::KEYWORD
 
-    // Data of 'addonpart_tweak_node <nodenum> <posX> <posY> <posZ>'
     if (m_context->isTokFloat(1) && m_context->isTokFloat(1) && m_context->isTokFloat(2) && m_context->isTokFloat(3))
     {
         NodeNum_t nodenum = (NodeNum_t)m_context->getTokFloat(1);
@@ -421,3 +423,114 @@ void AddonPartUtility::ProcessTweakNode()
         LOG(fmt::format("[RoR|Addonpart] WARNING: file '{}', element '{}': bad arguments", m_addonpart_entry->fname, m_context->getTokKeyword()));
     }
 }
+
+void AddonPartUtility::ProcessTweakFlexbody()
+{
+    ROR_ASSERT(m_context->getTokKeyword() == "addonpart_tweak_flexbody"); // also asserts !EOF and TokenType::KEYWORD
+
+    // TBD: add `null` token type to GenericDocument, so these params can be made optional
+    if (m_context->isTokFloat(1) && // ID
+        m_context->isTokFloat(2) && m_context->isTokFloat(3) && m_context->isTokFloat(4) && // offset
+        m_context->isTokFloat(5) && m_context->isTokFloat(6) && m_context->isTokFloat(7) && // rotation
+        m_context->isTokString(8)) // media
+    {
+        const int flexbody_id = (int)m_context->getTokFloat(1);
+        if (!m_tuneup->isFlexbodyProtected(flexbody_id))
+        {
+            if (m_tuneup->flexbody_tweaks.find(flexbody_id) == m_tuneup->flexbody_tweaks.end())
+            {
+                TuneupFlexbodyTweak data;
+                data.tft_origin = m_addonpart_entry->fname;
+                data.tft_flexbody_id = flexbody_id;
+                data.tft_offset.x = m_context->getTokFloat(2);
+                data.tft_offset.y = m_context->getTokFloat(3);
+                data.tft_offset.z = m_context->getTokFloat(4);
+                data.tft_rotation.x = m_context->getTokFloat(5);
+                data.tft_rotation.y = m_context->getTokFloat(6);
+                data.tft_rotation.z = m_context->getTokFloat(7);
+                data.tft_media = m_context->getTokString(8);
+                m_tuneup->flexbody_tweaks.insert(std::make_pair(flexbody_id, data));
+            
+                LOG(fmt::format("[RoR|Addonpart] INFO: file '{}', element '{}': tweaking flexbody {}"
+                    " with params {{ offsetX={}, offsetY={}, offsetZ={}, rotX={}, rotY={}, rotZ={}, media={} }}",
+                    m_addonpart_entry->fname, m_context->getTokKeyword(), flexbody_id, 
+                    data.tft_offset.x, data.tft_offset.y, data.tft_offset.z,
+                    data.tft_rotation.x, data.tft_rotation.y, data.tft_rotation.z, data.tft_media[0]));
+            }
+            else if (m_tuneup->flexbody_tweaks[flexbody_id].tft_origin != m_addonpart_entry->fname)
+            {
+                m_tuneup->flexbody_tweaks.erase(flexbody_id);
+
+                LOG(fmt::format("[RoR|Addonpart] INFO: file '{}', element '{}': Conflict of tweaks at flexbody '{}', addon parts '{}' and '{}'",
+                    m_addonpart_entry->fname, m_context->getTokKeyword(), flexbody_id,
+                    m_tuneup->flexbody_tweaks[flexbody_id].tft_origin, m_addonpart_entry->fname));
+            }
+        }
+        else
+        {
+            LOG(fmt::format("[RoR|Addonpart] INFO: file '{}', element '{}': skipping flexbody '{}' because it's marked PROTECTED",
+                m_addonpart_entry->fname, m_context->getTokKeyword(), (int)m_context->getTokFloat(1)));
+        }
+    }
+    else
+    {
+        LOG(fmt::format("[RoR|Addonpart] WARNING: file '{}', element '{}': bad arguments", m_addonpart_entry->fname, m_context->getTokKeyword()));
+    }
+}
+
+void AddonPartUtility::ProcessTweakProp()
+{
+    ROR_ASSERT(m_context->getTokKeyword() == "addonpart_tweak_prop"); // also asserts !EOF and TokenType::KEYWORD
+
+    // TBD: add `null` token type to GenericDocument, so these params can be made optional
+    if (m_context->isTokFloat(1) && // ID
+        m_context->isTokFloat(2) && m_context->isTokFloat(3) && m_context->isTokFloat(4) && // offset
+        m_context->isTokFloat(5) && m_context->isTokFloat(6) && m_context->isTokFloat(7) && // rotation
+        m_context->isTokString(8)) // media
+    {
+        const int prop_id = (int)m_context->getTokFloat(1);
+        if (!m_tuneup->isFlexbodyProtected(prop_id))
+        {
+            if (m_tuneup->prop_tweaks.find(prop_id) == m_tuneup->prop_tweaks.end())
+            {
+                TuneupPropTweak data;
+                data.tpt_origin = m_addonpart_entry->fname;
+                data.tpt_prop_id = prop_id;
+                
+                data.tpt_offset.x = m_context->getTokFloat(2);
+                data.tpt_offset.y = m_context->getTokFloat(3);
+                data.tpt_offset.z = m_context->getTokFloat(4);
+                data.tpt_rotation.x = m_context->getTokFloat(5);
+                data.tpt_rotation.y = m_context->getTokFloat(6);
+                data.tpt_rotation.z = m_context->getTokFloat(7);
+                data.tpt_media[0] = m_context->getTokString(8);
+                if (m_context->isTokString(9)) data.tpt_media[1] = m_context->getTokString(9); // <== Optional Media2 is specific for prop
+                m_tuneup->prop_tweaks.insert(std::make_pair(prop_id, data));
+            
+                LOG(fmt::format("[RoR|Addonpart] INFO: file '{}', element '{}': tweaking prop {}"
+                    " with params {{ media1={}, offsetX={}, offsetY={}, offsetZ={}, rotX={}, rotY={}, rotZ={}, media2={} }}",
+                    m_addonpart_entry->fname, m_context->getTokKeyword(), prop_id, data.tpt_media[0], 
+                    data.tpt_offset.x, data.tpt_offset.y, data.tpt_offset.z,
+                    data.tpt_rotation.x, data.tpt_rotation.y, data.tpt_rotation.z,
+                    data.tpt_media[1]));
+            }
+            else if (m_tuneup->prop_tweaks[prop_id].tpt_origin != m_addonpart_entry->fname)
+            {
+                m_tuneup->prop_tweaks.erase(prop_id);
+
+                LOG(fmt::format("[RoR|Addonpart] INFO: file '{}', element '{}': Conflict of tweaks at prop '{}', addon parts '{}' and '{}'",
+                    m_addonpart_entry->fname, m_context->getTokKeyword(), prop_id,
+                    m_tuneup->prop_tweaks[prop_id].tpt_origin, m_addonpart_entry->fname));
+            }
+        }
+        else
+        {
+            LOG(fmt::format("[RoR|Addonpart] INFO: file '{}', element '{}': skipping prop '{}' because it's marked PROTECTED",
+                m_addonpart_entry->fname, m_context->getTokKeyword(), (int)m_context->getTokFloat(1)));
+        }
+    }
+    else
+    {
+        LOG(fmt::format("[RoR|Addonpart] WARNING: file '{}', element '{}': bad arguments", m_addonpart_entry->fname, m_context->getTokKeyword()));
+    }
+}
diff --git a/source/main/resources/addonpart_fileformat/AddonPartFileFormat.h b/source/main/resources/addonpart_fileformat/AddonPartFileFormat.h
index bd44c6bd8c..317c6d4cc1 100644
--- a/source/main/resources/addonpart_fileformat/AddonPartFileFormat.h
+++ b/source/main/resources/addonpart_fileformat/AddonPartFileFormat.h
@@ -57,12 +57,14 @@ class AddonPartUtility
     void ProcessManagedMaterial();
     void ProcessProp();
     void ProcessFlexbody();
+    void ProcessTweakWheel();
+    void ProcessTweakNode();
+    void ProcessTweakFlexbody();
+    void ProcessTweakProp();
 
     // Helpers of `ResolveUnwantedAndTweakedElements()`, they expect `m_context` to be in position:
     void ProcessUnwantedProp();
     void ProcessUnwantedFlexbody();
-    void ProcessTweakWheel();
-    void ProcessTweakNode();
 
     // Shared state:
     GenericDocumentPtr m_document;
diff --git a/source/main/resources/tuneup_fileformat/TuneupFileFormat.cpp b/source/main/resources/tuneup_fileformat/TuneupFileFormat.cpp
index 884dd93f79..f3e77b71e8 100644
--- a/source/main/resources/tuneup_fileformat/TuneupFileFormat.cpp
+++ b/source/main/resources/tuneup_fileformat/TuneupFileFormat.cpp
@@ -187,7 +187,7 @@ Ogre::Vector3 RoR::TuneupUtil::getTweakedPropRotation(CacheEntryPtr& tuneup_entr
     if (itor == tuneup_entry->tuneup_def->prop_tweaks.end())
         return orig_val;
 
-    Ogre::Vector3 retval = itor->second.tpt_rot;
+    Ogre::Vector3 retval = itor->second.tpt_rotation;
     ROR_ASSERT(!isnan(retval.x));
     ROR_ASSERT(!isnan(retval.y));
     ROR_ASSERT(!isnan(retval.z));
@@ -268,7 +268,7 @@ Ogre::Vector3 RoR::TuneupUtil::getTweakedFlexbodyRotation(CacheEntryPtr& tuneup_
     if (itor == tuneup_entry->tuneup_def->flexbody_tweaks.end())
         return orig_val;
 
-    Ogre::Vector3 retval = itor->second.tft_rot;
+    Ogre::Vector3 retval = itor->second.tft_rotation;
     ROR_ASSERT(!isnan(retval.x));
     ROR_ASSERT(!isnan(retval.y));
     ROR_ASSERT(!isnan(retval.z));
diff --git a/source/main/resources/tuneup_fileformat/TuneupFileFormat.h b/source/main/resources/tuneup_fileformat/TuneupFileFormat.h
index 93437733fd..b0cbe1f909 100644
--- a/source/main/resources/tuneup_fileformat/TuneupFileFormat.h
+++ b/source/main/resources/tuneup_fileformat/TuneupFileFormat.h
@@ -59,7 +59,7 @@ struct TuneupPropTweak //!< Data of 'addonpart_tweak_prop <prop ID> <offsetX> <o
     PropID_t        tpt_prop_id = PROPID_INVALID;
     std::string     tpt_media[2];                     //!< Media1 = prop mesh; Media2: Steering wheel mesh or beacon flare material.
     Ogre::Vector3   tpt_offset = Ogre::Vector3::ZERO;
-    Ogre::Vector3   tpt_rot = Ogre::Vector3::ZERO;
+    Ogre::Vector3   tpt_rotation = Ogre::Vector3::ZERO;
     std::string     tpt_origin;                       //!< Addonpart filename
 };
 
@@ -68,7 +68,7 @@ struct TuneupFlexbodyTweak //!< Data of 'addonpart_tweak_flexbody <flexbody ID>
     FlexbodyID_t    tft_flexbody_id = FLEXBODYID_INVALID;
     std::string     tft_media;
     Ogre::Vector3   tft_offset = Ogre::Vector3::ZERO;
-    Ogre::Vector3   tft_rot = Ogre::Vector3::ZERO;
+    Ogre::Vector3   tft_rotation = Ogre::Vector3::ZERO;
     std::string     tft_origin;                       //!< Addonpart filename
 };