See also:

Deactivating DSC: DSC OFF
When DSC is deactivated, driving stability is reduced during acceleration and when driving in bends. To increase vehicle stability, activate DSC again as soon as possible. Deactivating DSC ...

Close the windows and glasssunroof
Driving with the glass sunroof and windows open results in increased air resistance and raises fuel consumption. ...

Remove attached parts following use
Remove auxiliary mirrors, roof or rear luggage racks which are no longer required following use. Attached parts on the vehicle impair the aerodynamics and increase the fuel consumption. ...