Compare the Bentley Arnage R 6.8 V8 Twin Turbo - [2006] vs Porsche 968 3.0 Turbo - [1992]. 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 Bentley Arnage R 6.8 V8 Twin Turbo or the Porsche 968 3.0 Turbo. We'll leave it up to you to decide which is your favourite.