http://blogs.motortrend.com/6236999/...car/index.html

sample quote:

Above 75mph aerodynamic drag accounts for about 50 percent of the total dynamic resistance a typical sedan must overcome. The regular C-class has a very competitive drag co-efficient of 0.27, but by adding smooth underbody cladding to reduce turbulence, partially blanking off the grille to reduce the airflow into the engine compartment, sealing the joins between the hood, headlights and bumpers, lowering the suspension half an inch, and ensuring the wheels and the mirrors were aerodynamically optimized, the engineers were able to improve the drag co-efficient seven percent, to 0.25.[/align] To reduce friction losses the regular power steering assembly was fitted an additional valve that switches off the servo pump when it senses the car has been travelling in a straight line for a time. Mercedes says this small modification improves gas mileage by about two percent. A new taller final drive features improved bearings, forged gears and lightweight construction to reduce friction and cut engine revs while cruising.[/align]

 

Seems like alot of work for very little return. But then again if you add up the percentage over several years that could be alot of money saved on gas.

 

it is no longer "politically correct" to brag about it
but those same small detail changes
also enable
higher speeds on the Autobahn
plus,
better fuel economy at 140 mph