Forgive me for asking---

We had the same truck (2008 GMC 2500, 4X4, CC, 6.5 bed) with a Lance 825 weighing I think about 2400 lbs loaded up. We added the stable loads, sway bar and airbags. The stable loads were great - and you can disengage them when not in use. We were pretty good with just the stable loads and sway bar, but used the air bags just to level out (about 30 psi left & 40 psi right). Overall the setup was really stable, not much sway at all. I've never used the Timbrens, but we were really happy with the stable loads and would definitely recommend them. To save money, have you thought about installing them yourself? The springs are already drilled, so it's just bolting things together.

Edit: we also had the Rancho shocks - they also made a big difference and was money well spent.