Compare the Mercedes GT R 4.0 V8 Bi-Turbo - [2016] vs AC Cobra 427 - [1966]. 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 AC Cobra 427. We'll leave it up to you to decide which is your favourite.