I found
this site which aims to be a repository of Blender models under the Blender Artistic License. They have 4 car models (look under "Auto"). I haven't looked at any of them yet so I have no idea how complex they are, or anything. The cars seem to be an Audi TT, a Bugatti, some sorta Mini Cooper, and a Lotus Elise. All four would probably be pretty cool in the game. If anyone's looking to contribute a car and doesn't have a model to start with, this would be a good place to find one. I might spend a little time with these models once I get done with the S2000...If you know of another place to get free models of cars please post. Remember they must be free as in freely distributable, not just free of charge.
