2018 Porsche 911 GT2 RS - The best way to describe the GT2 RS is that it’s a cross between the 911 Turbo S and the 911 GT racing cars being flogged in endurance races worldwide. The engine has been lifted from the Turbo S, but the 3.8-litre twin-turbo flat six’s power output has been bumped from 580 to a staggering 700 horsepower at 7000 rpm, thanks in part to the fitting of larger turbochargers and a revised air intake.