Collection of car modding information, as I stumble uppon. Hope it can serve as a starting point. Happy modding 
sources: Si3v, ac forums, rd forums
Q: How many taxtures can be used for a car ?
A: We don't exeed 20 materials per car. Each material can use different texture stages. Textures size limit is 8192x8192 but I suggest to not exeed 2048x2048 (4096x4096 only if you can't split). AC can use dds and png. Strongly recomended to use dds (compressed normal maps, dxt5_nm and 3Dc not supported)
Q: Will there be any kind of visual damage?
A: Under development, not sure for 1.0 (graphical damage, physical one will be included)
Q: LODs and their respective polycount ?
A: 3 lods. We use 60k for lodA, 20k for lodB and 5k for lodC
Q: Is the Ambient Occlusion map baked into a separate texture ?
A: no AO in separate texture
Q: Bump maps or normal maps ?
A: normal maps (tangent space and object space supported)
Q: Are instances supported ?
A: No.
Q: Aside from standard animations, will there be any auxiliary moving parts in the cockpit ?
A: Not sure for 1.0
Q: Is instancing supported ?
A: NO instances
Q: Any editing possible in the SDK Editor ?
A: the editor is a "Materials and object Properties editor" it does ONLY that. WYSIWYG from your cad. The ONLY import file format is FBX 2012. Only DDS (not all types) and PNG are supported. I STRONGLY suggest to use DDS (the usual ones DXT1, DXT5, L, AL, RGB or ARGB).
Q: Lightmaps, Vertex paint ?
A: NO lightmaps, NO vertex paint, AO baked into the diffuse texture
Q: Multiple UV supported ?
A: Second UV's re only experimental at the moment, we have only one shader that uses a second uv for the normal map, but no car or track uses it. So consider it NO GO.
Q: Multimaterials supported ?
A: Multimaterials are supported but each submaterial will be split in a single material once imported. each subobject will receive a _SUBx postfix. I don't use them: some properties of the object are related to the name, so if there are changes in the cad materials or the number of subobjects ecc ecc the postfix will change, loosing all the parameters already set before. (the editor can save a file of persistence with ALL the changes made to materials and object properties, so when importing a project, it will appear exactly as like as when you saved your persistence.
sources: Si3v, ac forums, rd forums
Q: How many taxtures can be used for a car ?
A: We don't exeed 20 materials per car. Each material can use different texture stages. Textures size limit is 8192x8192 but I suggest to not exeed 2048x2048 (4096x4096 only if you can't split). AC can use dds and png. Strongly recomended to use dds (compressed normal maps, dxt5_nm and 3Dc not supported)
Q: Will there be any kind of visual damage?
A: Under development, not sure for 1.0 (graphical damage, physical one will be included)
Q: LODs and their respective polycount ?
A: 3 lods. We use 60k for lodA, 20k for lodB and 5k for lodC
Q: Is the Ambient Occlusion map baked into a separate texture ?
A: no AO in separate texture
Q: Bump maps or normal maps ?
A: normal maps (tangent space and object space supported)
Q: Are instances supported ?
A: No.
Q: Aside from standard animations, will there be any auxiliary moving parts in the cockpit ?
A: Not sure for 1.0
Q: Is instancing supported ?
A: NO instances
Q: Any editing possible in the SDK Editor ?
A: the editor is a "Materials and object Properties editor" it does ONLY that. WYSIWYG from your cad. The ONLY import file format is FBX 2012. Only DDS (not all types) and PNG are supported. I STRONGLY suggest to use DDS (the usual ones DXT1, DXT5, L, AL, RGB or ARGB).
Q: Lightmaps, Vertex paint ?
A: NO lightmaps, NO vertex paint, AO baked into the diffuse texture
Q: Multiple UV supported ?
A: Second UV's re only experimental at the moment, we have only one shader that uses a second uv for the normal map, but no car or track uses it. So consider it NO GO.
Q: Multimaterials supported ?
A: Multimaterials are supported but each submaterial will be split in a single material once imported. each subobject will receive a _SUBx postfix. I don't use them: some properties of the object are related to the name, so if there are changes in the cad materials or the number of subobjects ecc ecc the postfix will change, loosing all the parameters already set before. (the editor can save a file of persistence with ALL the changes made to materials and object properties, so when importing a project, it will appear exactly as like as when you saved your persistence.
