Originally posted by Lord Nicon 
 But I mean, still, if thats the case then whats in the the 8? 
Thats just nuts. 
 A W12 - ie. a 12 cylinder.
The S models are usually even more powerful than their regular "A" siblings.  For example the A4 can come with a V6 engine, but the S4 has a V8 and some extra goodies that make it sportier as Sammy said.
As for the A6/S6 most are Quattro.
Don\'t get me wrong I love BMW\'s as well, but Audi has come a long way since the 80\'s when many considered it a high priced VW.