First, these aren't rallies. Rallies are about navigation, not speed. But that's beside the point.
I've never found horspower to be a hinderance, even on ice.
Every special condidion (SC) race has it's own character and strategy. Even though Tahiti, Swiss Alps and the Cathedral courses are all dry unpaved surfaces, different car/settings/driving strategies apply to each.
Basically, you win SC events the same way you get to Carnegie Hall "practice, practice, practice". Go to the course practice mode, and try different cars, and compare lap times. While you're at it, learn the line thru these tracks. Even though you might feel pretty much at the mercy of the drift and slide, there are places on the tracks where you do, and do not want to be. A jump on one side of the road might set you up beautifully for the next turn, while you take it on the other side might lead to disaster. There's always that one turn where you spin out every time that you need to learn how to get thru. Practice, practice, practice alone on the track with different cars and settings.
Learn your differential settings!
Learn where it's acceptable to take a penalty! There are places where 5 seconds don't make any difference, and even will give you a net gain (e.g. use your opponent's back bumper as an "alternate brake" in a section that's going to be a crawl anyway. Other places, a 5 second penalty will just about ruin your chance of winning. Basically, they're not as bad in slow sections, really bad at the beginning of a fast section, and great if they can get you around your opponent. Fight dirty.
Know what you can do that won't give you a penalty, but should. E.g., you can bloody SLAM into a wall, as long as your tail end hits first. Not realistic, but the upshot is, that if you find yourself unavoidably going up to the wall, you should know how to bring the rear end around to save the penalty.
In most cases, you use power and steering to get around the course and don't use your brakes much at all. There's a certain "pendulum" driving that works well for me, where the idea is that you are always turning left, right, left, right, back and forth... and the degree to which you turn is governed as much by the gas as the steering wheel. Give more gas, your rear end comes around but you don't actually tighten your turn... you actually slow down...
remember that the way you are pointing is not the way the car wants to move... seperate direction of travel from attitude in your mind.
It's hard to explain driving on loose surface. But definitely try different cars for different tracks, learn the tracks, use the practice mode to keep track of times, learn how to tune your differentials, and learn when and where to risk a penalty.
Also, I'd take it one track in one direction at a time. IOW, once you win Grand Canyon one way in easy, go on and try it the same direction in medium and hard. I've found that going one way, then immediately racing the other way can give me a case of the spins... Pick a race, and keep with it until you win, then move on. Don't go from one track to another looking for the easiest. They're all very different.
