steering sensitivity is perfectly fine at 7.
adding onto what cslacr previously mentioned, if you're running a 4wd vehicle playing around with the torque distribution while keeping the front anywhere from 40-50 is a good idea. brake balance is another good thing to mess with, although i personally prefer more power in the rear.
however, if you're running a ds3, i would highly suggest mapping the throttle and brake to the right analog stick. without a doubt, having as precise control over your throttle is the best thing you can do in an offroad situation. unless you're running an evo, exits should preferably be taken with little throttle as you pass through the exit and steadily push more into the throttle, as you would with most rwd cars or cars on the track ;D angle is also extremely important. going sideways into any turn is something you should rarely ever want or have to do, as it will cost you speed, time, and a clean exit. a popular example of this is with (dont flame me please) ken block. last year he was pulling terrible results due to his tendencies to pull turns going sideways cuz lets face it, they look and feel badass, however, this year, he learned to correct that mistake and has found himself pulling up results 10 positions! higher than last years... although that could be due to many things, im sure the fact he treated each turn properly shaved seconds off.
and yes, rallying is all about precision (again, clean entrances and exits are key) and being careful. assuming you aren't being purposely collided with. you'll notice this when you're running a standard wrc car against gt-rs, for example, and while you're playing clean they're wrecking their cars and you can pull away from the pack with ease.
rant over, please lemme know if im off on any info. im just a kid with some decent rally experience, im no expert, and would actually very much appreciate criticism and advice.