I finally found and installed a good interior rear view mirror on the left and right sides of my car. I also cut off the rear view mirror mount on the side of my car and finished it off smooth. The interior mirrors work fine for rear view vision and also allows me to get closer to the mailbox to pickup mail since I don't have an exterior mirror to risk hitting the box with.
Since the state just got hit with a massive cold snap, there has been too much of a termperature change for me to know how much effect it had on the mileage. The mirror isn't missing, its just been relocated to the other side of the window glass. Fortunately, South Carolina stopped doing annual automobile inspections back in the early nineties, so I don't have that B.S. to worry around.
Here's my last major aero mod, second windshield covering the area from the front of the hood to the top of the windshield. This should get rid of the "A" pillar vortexes. I also added an outer side skirt so I have one side skirt parallel to the iinner edge of the tires and another side skirt parallel to the outer edge of the tires.