[JasonG]

The way I'm seing it is this,
The coupe/sedan rear shape creates more eddies creating a negative pressure area on the rear window and trunk.
With the wagon, the airflow seperates more cleanly. This leaves a neutral pressure zone without the reverse holding currrent.


As a Saturn nut, the sc1/sc2 are the same body, the engine is the difference. Single vs dual cams. Same goes for the sw (wagon) and the sl (sedan, sl was the manual everything stripped model, 40 mpg hwy in a 1995).
Sorry to drift OT.