The base version of the Audi TT Coupé has a cd value of only 0.30; for the Roadster it is 0.32. Thanks to an engine shroud and the aluminum structure of the body, the underbody is nearly completely smooth, which improves the flow of air around the car. Both body styles have grown 9 millimeters (0.35 in) and now measure 4,187 millimeters (13.74 ft) in length. The width of 1,842 millimeters (6.04 ft) and the height of 1,352 millimeters (4.44 ft) and 1,357 millimeters (4.45 ft) for the Coupé and Roadster, respectively, remain unchanged. The wheelbase measures 2,468 millimeters (8.10 ft).
