The 2013 models had various improvements and differences compared to the GT500 of 2012 including new front end sheet metal along with standard HID headlamps, along with a new LED tail light assembly. The new 2013 Shelby GT500 also had no grill, due to the massive amount of cooling required for the vehicle. Performance changes included twin fuel pumps (a Mustang GT's single supply pump, twice over), larger fuel injectors, a grippier and larger-diameter clutch, a larger fan, a three-row intercooler (the previous car used a double-row unit), a beefed-up Tremec TR-6060 six-speed manual transmission with an internal oil pump, and a single-piece carbon-fiber driveshaft. Larger Brembo front disc brakes with six-piston calipers, reinforced axle tubes, and aero tweaks to help the car reach + safely. According to Ford, the changes have resulted in a 14-percent reduction in drag and a 66-percent increase in front-end downforce. Also new for 2013 was a larger front anti-roll bar and retuned springs. An rpm-adjustable electronic launch-control function was standard, as was a four-mode electronic stability control system.