We kind of got off on a tangent over on a 2015 F150 thread and I didnt want to highjack it with pictures of a 2006 FX4 LOL! So I will redirect them here to a relavent section.
I put this Air Lift auto leveling kit on my 06 FX4 in 2007. I had put a front leveling kit on the truck but I hated the sagging, motor-boating effect any time I towed or hauled something.
This kit was the best mod I've ever done to a truck of mine.
Front leveling spacers installed, air leveling kit installed, ride height set.
Truck under load from boat trailer..before auto leveling kicked in. (key off)
Key on and 15 seconds later.....auto leveled.