If you compare the 2014 Jaguar XKR-S GT to the XKR-S (the non-GT version) you will notice they both sport the same engine. That engine is a supercharged 5.0 liter V8 making 550 horsepower. That main difference between the Jaguar XKR-S and the XKR-S GT comes in the track friendly bits.
The XKR-S GT comes with a cool aerodynamics package which includes carbon fiber dive planes, front splitter, extended wheel arches, a rear diffuser, a carbon fiber rear wing, and an aluminum under-tray. You also get carbon ceramic brakes, wider 20-inch allow wheels, upgraded suspension, and tuned active exhaust.
The Jaguar XKR-S GT goes from 0-60MPH in under 4 seconds with a top speed of 186MPH. The bad news is that only 25 of these cars will be sent to the US and the cost is $174,000.