I've got a 2002 GMC 2500HD 8.1 large block gasser with 105,000 miles on it and I'm getting ready to put some Bilstein 5100s on it. It finally got to where over the past few years the originals were not dampening enough and my large 5'er would start to porpoise. I put some heavy duty gas shocks on my previous truck and they made it ride like a truck. Well, at any rate, the ride was much different, but not in a good way. That's part of the reason I waited so long, I liked the way the truck rode, and I didn't want to ruin it.