The special 2015 Mustang GT Premium coupe had the look of a high performance machine from head to toe, and the horsepower and torque numbers certainly did not lie. Powered by a mean 5.0L V 8 motor, the 2015 Performance Packs and 50th Anniversary Mustangs could put down more than 420 hp and 390 lb ft of torque. All of that horsepower and torque could meet the pavement thanks to the 19 wheels and Brembo Six Piston Front Brake Calipers with Larger Rotors. Speaking of the brakes, the strut tower brace and distinct front spoiler helped direct cool air to the area, which paid major dividends at performance driving events. 2015 Mustang GT Performance Package The S550 GT Performance Packs had a distinct ride to them thanks to the unique suspension tune and heavy duty springs.