Prior to 2010, the Shelby Ultimate Aero was the production car with the Guinness World Record for speed. It was beaten back in 2010, but remains a staple of speed. The TT, to those who aren’t familiar, is for twin-turbo., as it is the upgraded version of the Ultimate Aero, putting out a bit more power than earlier versions, with about 100 increase in hp and over a 200 lb increase in torque.