I forgot to put up pictures of the minor update I did to the front end.
The headlight covers are attached at the bumper and the top is just resting against the headlight bezel. The center section is attached at the hood and just resting on the bumper. That way I can still open the hood without a huge amount of work. It seems like it made the car a bit quieter but I have not seen a mileage increase. Mostly because the gas tank is leaking and I have a bad O2 sensor. I am holding around 59mpg with those problems so I think it is doing pretty good. Now that the weather is good I will probably change over to a 4 wire O2 and fix the gas tank soon.
I still have not figured out why it gets worse mileage with the underbody panels than it does with the ventilated bumper but it works good enough I am probably just not going to mess with it anymore. I am thinking the next thing would be to add to the rear sides and make bigger rear wheel skirts. But I think the easy gains are all done now so it is going to be expensive to really push it much higher with normal driving.