I just put the Thuren springs, Bilstein 5160 shocks, Carli trackbar, Steering box brace, longer swaybar endlinks and Kore bumpstops on my '06 cummins 2500. It rides SO much better. I no longer feel like I'm going to be catapulted through the roof of my truck with every speed bumpish type bump I hit. Washboard roads that limited me to 25-30 mph before I can now cruise at 55(easily :Wow1: ).
The only thing I'm not totally sure was worth it was, the Kore bumpstops, but they were like $85 shipped and compared to the Carli or Thuren stops they were alot cheaper and easier to install. So I'm not into them too much if I decide to ditch them.
With all these new parts it has really brought to my attention the fact that my upper balljoints are shot. I was planning on doing new tires next, but I think some of the Carli balljoints are next(once I can find some).
I have a hellwig anti-swaybar coming for the rear later this week. I use a truck camper with my truck and I'm trying to reduce some of the body roll.
There's plenty of stuff you can do to these trucks to make them more nimble offroad, but the deciding factor, usually, is how much and how fast you can bankroll the mods.
Checkout Carli, Thuren, Kore.
-Chris