If you play in the max out my car and decimate all style the dirt/snow events will trip you up.
It really is fun to just power slide around and let the tail of the car skirt the wall, but it equates to slow lap times even if it feels like you are really moving. Better to manage your entry speeds, slow in, fast out indeed. The AI are not great at dirt so you can beat them with inferior equipment to a point.
The best tip would be to run the easy and normal race over and over. Learn the track and make some credits for the effort. Normal would be better, more credits for one, a better prize car too. Try to keep up with the AI wait till last lap to pass. Watch what they do. I like to do a ride along with Bob driving to get a feel for the lines and braking points.
I know earlier posts make it sound like I wanted to hijack the thread a little, sorry. for that. I was just stoked my ragged old PS2 decided it could run GT4. Applying the things I have learned from 5 and 6 has given it a new feel for me.