I hear that a lot, and I think it would be a huge waste of money to change to an nVidia card when my 5750 runs all my other games just fine. Racer is the only game with the 8-bit shadows and the blocky lighting, so maybe its time Racer changed and got some better support for ATI users.
I love Racer, and I wish I could play it with proper shadows and lighting like all the nVidia users can, but without having to throw out my perfectly good video card. ATI makes up the other 50% of the video cards out there and I don't understand why Racer doesn't have better support for ATI by now.