I can't attribute it soley to my Edge w/Att because I installed it, the AFE/TT/PG7 and did the TSB all about the same time. I don't know if one of these mods was the sole contributor or if it was a combination of them all.
BUT ... . My mpg's went up about 1. 5 - 2 mpg city and about 2. 5 - 3 highway. All these things were done in my quest for better mpg's, not HP or torque increases.
I keep it set at level 3 for around town. Rarely ever go above 3 ($2. 39/gallon!).