Compare the Mercedes GT AMG S Roadster 4.0 V8 Bi Turbo - [2020] vs Vauxhall-Opel VXR8 GTS 6.2 V8 - [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 AMG S Roadster 4.0 V8 Bi Turbo or the Vauxhall-Opel VXR8 GTS 6.2 V8. We'll leave it up to you to decide which is your favourite.