Compare the Mercedes SL Class 500SL V8 R107 - [1980] vs Pontiac G6 GTP 3.9 V6 - [2006]. 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 SL Class 500SL V8 R107 or the Pontiac G6 GTP 3.9 V6. We'll leave it up to you to decide which is your favourite.