I normally use a two camera setup, which you can see here on reversed version of the course in j-rho's video:
El Toro 081714 - YouTube
However, I think with only one camera, j-rho's angle is about the best you'll get while still including driver inputs. I've tried mounting it inside the rear window, as far forward as possible, which worked alright (
AAA 112313 Practice Jeff - YouTube), but you can see the white balance is pretty bad. Perhaps with spot metering mode and the camera aimed properly at the middle of the windshield it would look better.
The biggest thing you can do to improve the quality of your videos is to get better sound. Newer GoPros may be better, but on the Hero1 and Hero2, the mics are horrible. I use a $50 stereo mic (
http://amzn.com/B00006HOLL) with a right angle adapter (
http://amzn.com/B008SFSIXU). You can see it at the top of the "driver cam" in the first video I linked. It has a custom fuzzy thing that I sewed on to it do reduce wind noise, but I'm not sure how much it really helps.
EDIT: Aw snap, beat to the punch by NoGrip on the external mic advice.