Compare the Mercedes SLR Class McLaren 722 S Roadster - [2008] vs Audi R8 GT 5.2L V10 - [2011]. 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 Mercedes SLR Class McLaren 722 S Roadster or the Audi R8 GT 5.2L V10. We'll leave it up to you to decide which is your favourite.