Compare the Mercedes CLK 63 AMG Black Series - [2007] vs Alfa-Romeo 8C Competitzione - [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 Mercedes CLK 63 AMG Black Series or the Alfa-Romeo 8C Competitzione. We'll leave it up to you to decide which is your favourite.