Every year I do an upgrade here or there for the truck or trailer. As the truck is starting to get long in the tooth I thought it time to give the rear springs a little support so I have ordered a set...
I used SumoSprings in the 1500# variety. No jarring at all and the load just sits on the overload springs. You might consider the SuperSprings also if you don't have overloads. They do work as spring packs do wear and flatten out. Another option is a full length add-a-leaf. Usually any good spring shop can make you one and supply all the needed u-bolts, pins, etc.