Compare the Mercedes GT R 4.0 V8 Bi-Turbo - [2016] vs Mercedes SLS Electric Drive AMG - [2013]. 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 GT R 4.0 V8 Bi-Turbo or the Mercedes SLS Electric Drive AMG. We'll leave it up to you to decide which is your favourite.