The Mk6 Golf was designed by Volkswagen's chief designer Walter de'Silva. The design is said to be more aerodynamic, helping fuel efficiency, and is quieter than its predecessor. Following criticism of the downgraded interior trim quality of the Mk5 Golf in comparison to the Mk4, Volkswagen opted to overhaul the interior to match the quality of the Mk4 Golf, while maintaining the same user friendliness from the Mk5. The car is also cheaper to build than its predecessor; Volkswagen claims it consequently will be able to pass these savings on to the customer. The Mk6 Jetta was released in Mexico in mid-2010, and by late 2011 it was available in all markets. Turbocharged Direct Injectiondiesel engines which uses common rail injection technology replaced the longstanding Pumpe Düse (PD) Unit Injector system. New on the Golf is the optional Volkswagen Adaptive Chassis Control (not available in the North American market), which allows the driver to select between 'normal', 'comfort', and 'sports' modes, which will vary the suspension, steering, and accelerator behavior accordingly.