2013-2014 Shelby GTS: Building on the popularity of the Shelby GT program, Shelby American introduced the new Shelby GTS model for 2011 and 2012 Mustangs. The GTS has been updated for all 2013 and 2014 Mustangs, V6, coupes and convertibles, manual and automatic transmissions. The Shelby GTS offers the unique styling, handling, and available performance upgrades you’ve come to expect from Shelby American. The performance possibilities are truly endless. Uniquely Shelby.