I agree with you Chuck, my WDH works very well and we are very close to being level when traveling. I don't really need the air bags but I like to play with stuff like that.
On my F-250 the air bags level me out when I tow my fifth wheel cargo trailer but I do understand that the weight is not being distributed. The bags do a good job of keeping the suspension from hitting the bump stops.
I've not been able to find any aftermarket. I traded a set from one 08 to another. It worked , nut I'll have to buy an aftermerket self leveling compressor to make thm work. I know for a fact that the factory bags ride LOTS smoother when empty or loaded and they stil actuallt work very well w/ the WDH.
It's a pain to fill them. The solenoids are always closed unless energized. My plan is to get a air lift compressor with a self leveler and wire them to a keyed hot with the solenoids. That way when the car isn't running no air will leak out. I hope my theory plays out.