Just bought a really nice 2011 GMC 3500 dually 4x4 with only 19k miles a few days ago and have already put 1300 miles on it. It appears to be mostly stock other than a S&B intake and 61 gal. aftermarket fuel tank. We spend a LOT of time pulling our 16k lb 5th wheel rv around the west and there are mountains every direction we go. We had been using my hotrodded '97 dodge 3500 but decided to get something newer. I've never left anything stock in my life so this will get some changes. The biggest issue now is the "chucking" on any uneven surface, that's when the 5th wheel bumps the truck fore & aft and it gets annoying quickly. I have some ideas to modify the rear suspension to lower it a couple inches and soften the spring rate a bit. I had the dodge sorted very well for towing and will get this one there too, eventually. I look forward to posting what I do in the other parts of the forums.
Ken
Ken