Compare the Ford Thunderbird 390 Convertible 3rd Gen. - [1961] vs Mini Cooper S R56 - [2006]. 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 Thunderbird 390 Convertible 3rd Gen. or the Mini Cooper S R56. We'll leave it up to you to decide which is your favourite.