Ok, so i am sick of the rear ed of this beast always looking saggy. I have the Front-end leveling kit and with no weight it sits level, but with passengers, the boat, or trailer it drops too much. I looked everywhere for a solution, but I don't like the idea of the Timbren's as they are way overpriced for a large "bumpstop" I have had airbags on every tow rig I've owned for the last 15 years. But no one makes them for the NV3500, just the 2500. Ok, with a full summer of towing behind me an getting flashed at "for having my brights on at night" i relented and ordered the 2500 Firestone kit #2551. Put it on this morning and it fits like a glove!!!! I cannot wait to hook up the trailer and tow this weekend. Now if i can just find a bigger tank the the puny piece of !@@#$%%^ fuel tank that comes in these Beasts.