the audi rs4 (quattro) will be released around july '96 timeframes. it will be powered by a twin turbo 2.7 litre v6. my dealer tells me that it will be 340-350hp (just above the bmw m3), and it should cost s2 type of money new.
apparently there will also be an rs4 avant, although i'm not too clear on this point. it seems that audi may continue to sell the s4/s6/s8? models as a top-of-the-range quattro options. ie the s4 would be the 30valve 2.8l v6 a4 quattro, while the rs4 is the performance model. still the dealer is a little vague on all this and is checking with ignolstadt for me.
the moral of the story thus far is :-
1) if you can wait to next year and,
2) if you can afford it,
3) buy the rs4. it'll me an awesome car if my drive of the 286hp mtm a4q is anything to go on.
i wouldn't purchase a new s6 now. i think resale values for this model will drop with the rs line coming out. 2nd hand is another story though. again, if you can wait a little after the formal rs4/rs6/rs8 announcements, there may be some good s6's on the market...