Made in Blender 2.70 for Cycles rendering. Rigged with constraints for physical simulations.
All you have to do is just drag CTRL-dummy (circle under the model) in place you want and hit ALT+A (or play
button on a timeline).
Layer 1 - contains Dummy model
Layer 11 - constraints for physical reaction
Layer 2 - contains Car-base
Layer 12 - constraints for physical reaction
FBX/Obj contains only dummy model without constraints.
Dummy has 5 textures with resolution 4096x4096 for your needs (color with scratches, plain color, bump, normals,
specular)