Compare the Audi A4 2.0T FSI Quattro - [2004] vs Audi A3 2.0tdi Quattro S-Line - [2008]. 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 2.0T FSI Quattro or the Audi A3 2.0tdi Quattro S-Line. We'll leave it up to you to decide which is your favourite.