CaryR,
Sorry, I haven't noticed any improvement in mileage. Our mileage has settled at around a handcalc'd 19. 5 - 20. 4 (15% - 20% city) for the last three tankfuls. We had already seen a9 - 20 before the AFE.
With no basis in fact, except perception, I do feel like there is better acceleration, maybe the extra air is helping the fuel to burn more efficiently.
I got the AFE with a view to add some 1. 5 EDM injectors, maybe, and/or a box. I'm not doing it for the power, though that would obviously be there. I'm really looking to maximize MPGs.
Hope this helps.
Jim