Well, I finally finished the install last night, and I couldn't possibly be more stoked with the results.
Prior to this install, I had a 1" block in the rear, still with factory Offroad Bilsteins. The rear end has always been STIFF going over bumps, and especially STIFFER when taking fast hits (pot holes at speed, washboard, etc.) I just dealt with it for quite a while, because a truck is supposed to be stiff... right? That was all fine and good until I started getting axle wrap. Not sure what caused it to begin, as I had no issue for about 30k miles-ish, but all of the sudden I was feeling it at every stop, and every start... not cool.
So, I wanted to stick with 1-1.5" of rear lift to accomodate my 3" front lift, but I certainly didn't want to make the ride stiffer than stock by adding an AAL. I did a bit of research and came across the Wheeler's Progressive 3-Leaf AAL package, which essentially replaces your factory overload leaf spring. Now, you supposeably lose 3-400lbs of capacity, but I don't tow or overload my bed often (ever?) so I wasn't awefully concerned with this. I decided to couple the new leafs with the Bilstein 5100s, due to a lot of the recommendations that I've read around here.
Just finished the install last night and took the truck for a ride. What I found was jaw-dropping... I really don't know if I've felt a better riding truck, ever. I'm absolutely astounded by the bump-eating capability of the truck's rear end now. I haven't had a chance to find any extremely rough washboard, but the washboard that I did find were easily soaked up by the setup. I've purposely driven the truck over some hits that used to send my rear end sideways, and the truck just soaks them up now... absolutely amazing.
In short, if anyone's looking for a reasonablely priced solution to a rough riding rear end, I think I would highly recommend this setup. I'll try to get some pics up whenever I find my camera cord, but feel free to ask any questions and I'll do my best to help. Gotta love Wheelers, those guys are simply amazing!