Well....I didn't see any mileage improvement but I didn't see any decrease either. I went from bolt-ons to 5 psi to 10psi boost and saw no change in mileage.

I don't drive real fast all the time...I just get to the speed I want to drive REALLY quick! Others that have ridden in my truck are impressed with the mileage that I get considering the HP and the way I drive.

As soon as my wife gets over her stroke from my tranny crapping out, I'm getting Allen to tune her 'burb for economy/performance.