Compare the Jaguar XJ R-15 6.0 V12 - [1991] vs Fiat 500 1.4 T-Jet Abarth Essessee - [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 Jaguar XJ R-15 6.0 V12 or the Fiat 500 1.4 T-Jet Abarth Essessee. We'll leave it up to you to decide which is your favourite.