Compare the Mercedes GT AMG Black Series 4.0 V8 Bi Turbo - [2020] vs Bentley Bentayga 4.0 V8 Bi Turbo - [2018]. 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 AMG Black Series 4.0 V8 Bi Turbo or the Bentley Bentayga 4.0 V8 Bi Turbo. We'll leave it up to you to decide which is your favourite.