That is sort of personal and also dependent maybe on hardware. I use a 4.1 audio system with bass and buttkicker. I like to feel the sound enter my body...not only through my ears with headphones. So my settings might be very diff from others who use headphones. But in general, turn up player engine and tire volume. Turn down opponents engine volume and menu sounds. All the other minor sound settings in between I have from 18-34.
