Compare the Audi 80 GT 1.8 - [1975] 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 Audi 80 GT 1.8 or the Mercedes 300 SEL 3.5. We'll leave it up to you to decide which is your favourite.