Compare the BMW 6 Series 650 4.4 V8 - [2014] vs Mercedes SL Class 55 4Matic+ 4.0 V8 Twin Turbo - [2021]. 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 BMW 6 Series 650 4.4 V8 or the Mercedes SL Class 55 4Matic+ 4.0 V8 Twin Turbo. We'll leave it up to you to decide which is your favourite.