Compare the Audi R8 Spyder 4.2 V8 FSI Quattro S-Tronic - [2012] vs Audi A6 RS6 4.2T Quattro V8 - [2002]. Find out which car is the fastest, most powerful, lightest or has the biggest engine in our top trumps style comparison page. Find out which car has the highest top speed or is the fastest accelerating, is it the Audi R8 Spyder 4.2 V8 FSI Quattro S-Tronic or the Audi A6 RS6 4.2T Quattro V8. We'll leave it up to you to decide which is your favourite.