Compare the Citroen CX 25 GTi Turbo - [1984] vs Mercedes 300 SEL 3.5 - [1969]. 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 Citroen CX 25 GTi Turbo or the Mercedes 300 SEL 3.5. We'll leave it up to you to decide which is your favourite.