Compare the Saab 9-3 2.8t Aero Convertible - [2008] vs Chevrolet Cobalt SS 2.0 Supercharged - [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 Saab 9-3 2.8t Aero Convertible or the Chevrolet Cobalt SS 2.0 Supercharged. We'll leave it up to you to decide which is your favourite.