dodge guy wrote:
The air suspension will not cause the float feeling you describe. most likely it is because of an improperly setup WD hitch. a lot of people describe the feeling you have and just go out and get a bigger truck and use the same poorly setup WD hitch that is now masked by the heavier truck. read up on how to properly adjust a WD hitch with the air suspension (I believe Ford even has a page or 2 in the owners manual on how to do this!), then be sure you have the proper tongue weight and properly sized WD bars, too heavy a bar can cause the same issue because it will remove too much weight from the rear axle. then take it out and see how much better it handles.
Personally, I think this is great advice and if it was me, I would give this a try first. Especially for the length/weight you are towing. I used a similar TV (2007 1500 Suburban LTZ/4.10/6.0L with air ride), towing a bit longer TT, and didn't experience any float. Why waste any money if you don't have to.