Compare the Porsche Panamera GTS 4.8 V8 - [2011] vs Porsche 911 Targa 4 991 - [2014]. 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 GTS 4.8 V8 or the Porsche 911 Targa 4 991. We'll leave it up to you to decide which is your favourite.