If you have Firestones and real shocks instead of OEM you should not have a problem. Looking at the product it simply looks to cheesy to really be any help at all. All it looks like it does is put a spacer between your stock helper springs and their rubber bumpers putting them in play constantly. If Dodge had designed the OEM helpers right they would be in play as soon as you put a moderate load on the truck but, they didn't. Empty or barely loaded those things are going to make the truck ride like a tank in the rear. One of the things I recently noticed about Dodge Ram dually rear suspension, while I've been looking to buy one soon, is that those installed helper springs are rendered almost useless by the distance they are from making contact with the bumpers that actually put them in play. My first thought when I looked under there was, "wow, those are sure useless, the truck will be at a 20 degree angle nose up before the helpers even engage." They look like they are there for show and a false increase in GVW, not actual or legitimate use.
On my current Ford F250 truck they are about two inches from contact and come into play as soon as a moderate load is put on the truck. On the 2012 Ram dually they are about 5" from initial contact making them almost useless as helper springs. If your truck is porposing in back when you go over bumps add more air to the bags and go buy yourself some high quality adjustable shocks that will do the job. The original equipment non-adjustable shocks that came on your rig are useless garbage if you plan on hauling loads or a camper. I have Rancho adjustables and Firestones I put on my Ford many years ago that stopped all the bounce when I put the cabover on and haul my 22' ocean boat around. The bags get 100# and the shocks are set at position 9. When I haul the 33' 5'r, 30# and #5 position and no bounce. It's actually too stiff at position 9. Good shocks are the key, not a cheap fix that engages your helpers constantly. I can almost guarantee you won't like thet unloaded ride with those cheeesy things on your truck. If it looks too good to be true, it generally is and those look like something invented in someone's garage.