Al, I would make a bet that the EE air dam is a big reason that you are getting better gas mileage than others. The dam forces air to go around the truck, instead of bouncing around underneath it.
I have a 99 Limited front bumper(damaged) that I may use to have built a lower air dam, to affix to my Mountaineer. I like the look of the Saleen air dam also, so that would be my guide.
Where's Expo5.0, can we get him to build one, or two, or a bunch? LOL,
DonW