Dino:
I've run one tank of gas through my 08GT since I installed plastic panel to smooth airflow. The tank gave me 20.8mpg as opposed to a little under 20 on the previous tanks. The computer said I was getting 22.1mpg as opposed to 21.4 without the panel. I think it's a little early to say anything definite, but it is encouraging.
Anyway, thanks!. After a couple more tanks I post about it.
v/r
ken