Compare the Ford Sierra Sapphire RS Cosworth - [1988] vs Mini Cooper John Cooper Works Roadster - [2012]. 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 Ford Sierra Sapphire RS Cosworth or the Mini Cooper John Cooper Works Roadster. We'll leave it up to you to decide which is your favourite.