In general, you'll need a really soft suspension, a high ride heigth, with medium extention dampers and hard compression dampers (compression - extention = 3-4 difference, no more than 2 difference front/rear), medium antiroll bars (front = rear minus 1 or 2, same difference front/rear as your compression/extention dampers), a lot of camber (3-5°) and some rear positive camber (+0.3 - +0.5).
Usually, front damper are higher than rear's but it depends of where the weigth of your car is and how you like to drive on dirt. I don't know much of snow setups.
Torque repartition should be somewhere around 50/50 or 40/60 and your LSD front/rear should have even values, but for initial front = 2 * the rear (initial = ~32/~16 for exemple. Set other values at 20 and make races to try it, only after you're happy with your suspension setup).
These are general settings that comes from memory from my GT4 tuning experience, I don't experienced much GT5 rally setups now.
Also please note I have a crap memory, so I could have said Blueshift's bull****s as usual.
