Compare the Bentley Mulsanne Turbo R - [1992] vs Vauxhall-Opel Manta 400 2.4 - [1981]. 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 Mulsanne Turbo R or the Vauxhall-Opel Manta 400 2.4. We'll leave it up to you to decide which is your favourite.