From what I've heard, it should be the Toyota Tacoma x runner. But be aware: you will have to fully tune your car if you want your B-spec driver to win the race (he's a complete moron xD).
Note, this topic should be in the B-spec section of the forum .
I strongly agree with the Tacoma X-Runner. Max tune it. A better Bob will help, but he usually likes less weight in the vehicles. I didn't mess with the settings too much. Like someone above said, make sure you're pushing him the whole way.