I think your biggest mod to get better mileage is the pressure exerted by your right foot. When my foot gets heavy and I want to do 80mph, my mileage is crap. When I take it easy and do the posted limits, I can see close to 17-18 running empty.

 

AMAN to that!!!!!!LOL
I'm going to take an extreme step for the mpgs by trying the diff. switch. My machanic says he can get the 3.55 gears for my truck. I think he'll be able to get the 3.73 gears. We will see. I did tell him to get them regaurdless. (3.55s or 3.73s, whatever is available) If it doesn't work, I'll have the 4.10s put back in. My goal is to lower the RPMs while in cruise mode. I'll probably lose some power on the low end, but will regain it in the mid range, like my Supra.(that thing ROCKS)

 

I almost forgot, pump your tires up to the max psi on the tire itself. You have less resistance of friction. I know you may think that it will cause belt seperation, it hasn't for me. The ride may be a little rougher thans usual, but you want every little bit you can get in this day of fuel conseration.