[NeilBlanchard]

Thanks for the welcome!

I will take a look at the aero forum -- I'm thinking of a piece of heavy vinyl? And under the hatch area, behind the beam axle, I'm thinking a sheet of aluminum formed to keep the rear bumper fascia (and other bits under there) from becoming a sail...

The car really needs a 6-speed transmission -- at least 80% of the time I shift straight from 3rd to 5th. The only time I need 4th is in the winter in deep snow going ~30mph, so I can keep good traction and the right speed for the conditions.