Dont forget, MOST of the WR runs and setups are made with an UNREALISTIC setup, EXPLOITING a few bugs the physics have, which drives me INSANE.... not only that, but the WR laps are done tearing up the tranny and car, not REALISTIC at all, so dont gauge your speed by kids that will do anything including exploiting physics bugs to be fast (IE: having the front end 10 cms higher then the rear, in real life the car would have 0 grip on the front since its creating lift, damn exploiters)
Watch a few of my wr runs if i still have any :P, there you'll see realistic setups and lines and driving.
Also, i cant stress enough to learn the track! very good points made by the poster, follow them and you'll be set for some good races.