Sometimes raw power isn't the only upgrade that matters. Although the supercharged 5.0-liter V8 that powers the 2014 Jaguar XKR-S GT ($174,000) is the same as the standard XKR-S with an output of 550 hp, the GT is far better equipped to take on the track. Why? Well, it's the combination of a new aerodynamics package that includes a carbon fiber front splitter, dive planes, extended wheel arch spats, rear diffuser, an aluminum undertray, and a huge carbon rear wing, larger carbon ceramic brakes, wider 20-inch forged alloy wheels, a stiffer suspension, and a revised active exhaust system. The result? A street-legal racer that goes from zero to 60 in under four seconds, boasts a top speed of 186 mph, and will be limited to just 25 cars in the US when it goes on sale in August.