[lunarhighway]

i think the B class is a little larger than the golf, and the previous b class was a little higher than this model too, so mercedes had some room to lower the seats and free up some headroom that could be sacrificed for a better aero shape.

if the golf would have the same roofline as the B-class this would either impact rear passenger headroom, or if they chose to raise the front of the roof could increase frontal area.

but that said the comparison shows that with minimal changes in overall shape large differences in drag can be acieved. and with some carefull wiggeling a good compromise should be possible

i suppose this is why there's SUV's and crossovers comming out with rather surprising good drag coefficient, with their visual high stance it's easy to give or take a few centimeters to get a perfect roof profile, and a Cd that gives the impression they are as slippery as the sedan next to them (Cd x frontal area is still way over the heads of most buyers) especially when around 0.3 cd's are still marketed as "exeptional for it's class, etc..."