I have been using a similar product, SuperSway Stops, from Supersprings -http://www.supersprings.com/superswaystops_overview.asp - on my 2012 F250 FX4 Scab long bed. I installed them about a month into a three and a half month trip with our 1800 pound truck camper.
I was getting some sway when driving over uneven surfaces without them. Installing them helped quite a bit. This was my first experience with a truck camper so I donít have anything to compare to, but they do help keep the truck from rocking side to side.
If I have any complaint, it would be that there is a little spring slap when going over large bumps or dips. It isnít much and is almost nonexistent with a full water tank. I also have Firestone air bags installed and I donít know if that effects the performance of the SuperSway Stops. The problem is that when I air up the bags to level the truck, it raises the SuperSway Stops just slightly off of the overloads. All things considered, I would recommend this type of accessory.
I also have to say that the truck performed flawlessly for the whole ten thousand mile trip.
My slide-in weighs around 3,000 lbs fully loaded. I looked at those upper overloads and couldn't justify the price versus what they are - just an extended rubber bump stop.
After I got my F-350 home the first thing I did was put the camper on to test how the truck would sit and ride and handle without any aftermarket load helper add-ons. The weight of the camper settled the suspension just barely so the overloads were touching the factory stops, and the truck sat level. Handling was about the same as what I was used to with the older F-250 with AirLift old bags.
A thousand or so miles later I added a set of the stabil-loads, those funky little things that bolt onto the ends of the lower leaf springs. I didn't stack them as I wanted them far away from the springs while unloaded. The truck doesn't sit any higher, that's OK as it is still level, but there was a noticeable improvement in handling.
I think the lower stabil-loads are a far better choice than those upper bump stops.
By the way, I also purchased a set of AirLift springs but after 4,000 miles of hauling the camper I just don't see a need for them, and I probably won't install them.
And here are some picks, the instructions were off for mine but it still works. My truck sat a little low with a cap and tools so this spring brought the back end up 1.5"s or so and settles perfect when hitched up to my TT, about 900# tongue weight and I load about another 500 to 800 # of wood and other camping stuff in bed. It does ride stiffer unloaded but I left them in for the winter and its been fine on snow and ice without skipping around.
The shackle has not hit the overload stopper even though it looks close, I have had 2k# of wood pellets in the back and went over some bad RR Tracks a couple times this winter and never felt it bottem out or hit anything.
I did add a hose over the brake cable to prevent rubbing after the pics. The instructions show the cable in a different location.
I added the upper stable loads to my truck and it really helped with the sway when I am hauling my Lance Camper. My truck sat level without them but the sway was a little to much for me on windy days. My truck also has the camper package and Rancho 9000's and that's it. My only complaint is that the overloads slap the stable loads over bumps when the truck is empty. I trimmed the stable loads a little and got rid of most of the slapping. When I first installed the Stable Loads I was surprised to see how close they were to the overload leafs when the truck was empty.