ok, been waiting to post until I got some real mileage figures. Ready to be shocked?

Bone stock without tuner and no power as well.
143 miles, 5.76 gallon that's 24.8 mpg!
Bone stock without tuner gutted convertor, no air filter, new plugs, new upstream o2, 127 miles,4.82 gallon, that's 26.3mpg!!!
New parts, gutted convertor, No air filter 87 tune,178 miles, 8.76 gallons. 20.31 mpg!!!
New parts, gutted convertor, no air filter, tow tune with 70 mustang and 16 ft trailer, 137 miles, 9.71 gallons, 13.1 mpg. 65-75 mph
91 tune, 83 miles, 5.35 gallons, 15.5 mpg!
every test was at 55mph with the cruise on empty except for the tow tune setting. Get ya some of that!!!!
If you own a newer vehicle and you don't have some kind of programmer, your crazy for not! The power difference is incredible!
I haven't tried the mileage setting as of yet but I will be soon.