I want to thank you all...
Your comments and your threads gave me the inspirations about improving my good old Mazda 626 station wagon. Finally i got about 12% better MPG, and this with a few simple modifications.
So here's my feedback to you!
a) the spoiler gave me approx. 6% (Google for novel spoiler greencarcongress)
However i had to modify this spoiler. I had to remove the sharp edge on the rear. (Security for colliding bikers) I don't want to miss this part any more! It is great for fast driving on highway.
b) closing the gap between bumper and chassis with aluminium foil. This could be felt at driving. It is a quite big effect.
c) shielding the rear axle, shielding a gap in the underbody, and improving the exhausts aero properties. Small effects.
So i got 37 MPG @ 75 MPH
