Compare the BMW 6 Series M6 F13 - [2017] vs Mercedes CL Class 65 AMG Bi Turbo - [2003]. 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 M6 F13 or the Mercedes CL Class 65 AMG Bi Turbo. We'll leave it up to you to decide which is your favourite.