Compare the Ariel Atom 4 2.0 Turbo - [2019] vs Porsche 918 Spyder 4.6 V8 - [2013]. 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 Ariel Atom 4 2.0 Turbo or the Porsche 918 Spyder 4.6 V8. We'll leave it up to you to decide which is your favourite.