Compare the Porsche Panamera 3.0 V6 Turbo Diesel - [2011] vs Audi A5 3.0tdi Quattro Cabriolet - [2009]. 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 Porsche Panamera 3.0 V6 Turbo Diesel or the Audi A5 3.0tdi Quattro Cabriolet. We'll leave it up to you to decide which is your favourite.