IMO most newer (WRC type) rally cars are fine with stock settings. Adding the rollcage (rigidity option) and a fatter turbo (don't overdo it or you'll spin way too much) can help too. Cars with high torque and wide powerbands really make everything easier as you can control wheelspin much better. The group B cars seem to have a little more erratic handling, so I personally wouldn't recommend them over the newer cars if you want good clean laps. Best rally car for me so far is the '03 Impreza, but I haven't tried the new Evo RC yet. It's very predictable and turnable, it has loads of torque, and it's very easy to control your angle with it. The Impreza should also be more than enough to beat the hard dirt/snow races cleanly with a bit of practice (they're "hard" after all
)
As for racing tips... slow in fast out for hairpins, and start off at a moderate angle (set it up early). Try to keep countersteering at a minimum. For 90 degree or lesser corners, steer in way too early and floor it
You can usually adjust your turn radius while drifting just by steering slightly (I use sawing motions) while on full power).
I find it better to approach any normal corner with slightly less angle than you'd think would be needed, it seems to be easier to increase angle than reduce it while maintaining speed and line. It also seems like stabbing/sawing (on/off) input works well for dirt tracks, except in very slow corners like the tight S at Yosemite.
Key points is to set up turns/angle early and stay on the throttle. If you think you're gonna understeer into the wall, try turning in sharply and stab the throttle. Unless you're in a hairpin, this will probably keep you on track..
The biggest headache with these races is obviously the 5 sec penalty, so don't try to overtake on narrow sections unless you can slide past into a turn and block your opponent without exposing the front of your car (try to keep low angles when the AI car is right behind you). If you go wide, the AI WILL ram you, and if he clips your front wing you will get the penalty.
