I've experimented with many mounting points, here are some of my favorites..
I made this video from one of my Autocross events last year. I used side mount, in-car, and for the low front shots, I put a sticky mount on the front license plate frame (I normally drive with no front plate):
For the drag strip, this is my favorite:
Like others have stated, hanging the GoPro upside down from the sunroof is a good view. Here's another Autocross run: