Compare the BMW X6 M 4.4 V8 Turbo E71 - [2013] vs Bentley Continental GT 4.0 V8 Turbo Convertible - [3996]. 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 X6 M 4.4 V8 Turbo E71 or the Bentley Continental GT 4.0 V8 Turbo Convertible. We'll leave it up to you to decide which is your favourite.