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 ($174,000) is the same as the standard XKR-S with an output of 550 hp, the GT is far better equipped to take on the track. Why? Well, it's the combination of a new aerodynamics package that includes a carbon fiber front splitter, dive planes, extended wheel arch spats, rear diffuser, an aluminum undertray, and a huge carbon rear wing, larger carbon ceramic brakes, wider 20-inch forged alloy wheels, a stiffer suspension, and a revised active exhaust system. The result? A street-legal racer that goes from zero to 60 in under four seconds, boasts a top speed of 186 mph, and will be limited to just 25 cars in the US when it goes on sale in August.
If you plan on driving your Viper as much on the track as you do on the road, consider the 2014 SRT Viper TA ($TBA). Designed for optimal performance on road courses, the TA features an upgraded suspension with firmer levels of damping, retuned shock dampers, springs, and stabilizer bars, a lighter carbon fiber X-brace that replaces the standard aluminum part, upgraded Brembo brakes, and an advanced aerodynamics packages with carbon fiber front splitters and rear spoiler. It's still powered by a handcrafted, 8.4L aluminum V10 producing 640 hp, but unlike the standard model, only 33 cars — all decked out in Crusher Orange — will be available later this year.