I got the VW Bus race earlier today. On the 2nd to last corner, if you make your entry slightly wide, you don't have to hit your brakes at all, and you will catch several vans in front of you. But be warned, for some reason that area of the track is super sensitive to collisions. If you as much as tap the person in front of you, you will be DQ'd.
Its a gutsy move, but doing it allowed me to go from 5th to 2nd in that turn alone. I passed the guy in 1st place before the first corner on lap 2.