Compare the Audi A4 S4 4.2 Quattro Cabriolet - [2004] vs Mercedes G Class G 55 AMG Kompressor - [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 Audi A4 S4 4.2 Quattro Cabriolet or the Mercedes G Class G 55 AMG Kompressor. We'll leave it up to you to decide which is your favourite.