Stick to 195/65-15 size. The larger 205/65s or 215/65s are not only wider but are larger diameter, which has a bad effect on gearing. For rallyx, lower gearing is better to dig you out of slow combinations, and the bigger tires are like running a higher gear.
Narrower tread and a more open tread pattern gives better bite on soft dirt, grass, or mud. The big sizes work fine on a turbo car with 250 or 300 hp, but with an RS, that's not your problem.
Tire Rack has discontinued the excellent Kumho R700 gravel tire in the 195 size. Bumma. For new 195s, go for Yoko, Michelin or Falken. The advice for med compund is good, softs give a little better grip in the wet but the tradeoff in reduced tread life is not so great. If the courses you are likely to do are in hot conditions, forget the softs entirely--you'll cook em in a couple events.