I forgot to answer the air bag ?, oops.
I removed my overload spring pack, and installed Air Lift's 5000lbs bags. The overloads are really the culprit with the rough ride. As the suspension goes Thur it's travel upon impacting a bump. The overloads run into there stops, this results in a SLAP , the trucks suspension never got a chance to SOAK up the bump. So you end up with a very rough riding truck, which gets old about this time of the year with all the pot holes.
By removing the overloads, the suspension is allowed to go Thur it's full travel without the sudden stop the overloads use to cause. The resulting ride quality is fantastic. The Air Lift air bags, will allow the truck to maintain it's payload capacity, and they can be adjusted accordingly. One nice benefit from them is the highway ride. I like to add just enough air that they take the weight of the truck off the springs, this is 3500 truck heaven. You get a "riding on air" type of a ride, all the small bump and expansion joints go away.