Compare the Ultima GTR 720 - [2000] vs Koenigsegg Agera RS 5.1 V8 Twin Turbo - [2015]. 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 Ultima GTR 720 or the Koenigsegg Agera RS 5.1 V8 Twin Turbo. We'll leave it up to you to decide which is your favourite.