Well I did some aeromatics experiments lately with it and didn't find much (although it was not extremely scientific I admit)

I blocked off about %60 of the grill with cardboard inserts and was planning to remove just enough to keep it from running too hot but it never went over 200 F with the AC blasting in 93 F heat up a 3 mile long mountain grade so I never ended up removing any. I also blocked off most anywhere air was still entering the grill could sneek around the radiator instead of thru it including the air going into the air dam openings. I made some cardboard triangles to go on the front of the mirrors and put some tape over the cracks around the headlights and stuff in the front. I also made some cardboard "air directors" underneath the truck to smooth airflow around a few of the biggest objects like frame pieces and such....

I was trying to just do stuff I was wiling to live with if it worked and I could make more permanent stuff but for all that work I gained about 2 MPH coasting down the 3 mile mountain VS before the aero mods and maybe 1/2 MPG if I round up a little on the 200 mile round trip I have been making 3 times a week. A couple aero things left I would like to try would be basically a full belly pan but have yet to find a suitable material, thinking about robbing some Prius belly pans at a JY because of the way the air extractor holes are made on them. I also have contemplated a temporary ramp reaching from the rear/top of the cab all the way down to the rear edge of the lowered tailgate but so far the only things I have come up with would be pretty heavy... would just be for experimenting anyhow as I use the bed a lot and need easy access. Other than that I will make some permanent grill inserts out of a black plastic tote and uncover just enough to keep things cool and ditch the cardboard underneath.