See also:

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. ...

Aerodynamic optimisation of underside panelling
As the excellent drag coefficient (cd = 0.26) would suggest, the aerodynamics of the new BMW 3-Series have been intensively honed in a state-of-the-art wind tunnel. The optimised aerodynamics also ...

Hot exhaust system
Hot exhaust system High temperatures are generated in the exhaust system. Do not remove the heat shields installed and never apply undercoating to them. When driving, standing at idle and whi ...