Thanks, everyone, for your inputs!
The coil-over idea does seem like a very nice set-up, but it is also costly. If my Tahoe was dedicated to heavy off-road all the time, then investing in coil-overs would make more sense. I think I will take it a step down until I know more about what the Tahoe can not do for my needs.
I do want to change the shocks and springs, at least. My Tahoe has 140K miles on it on the original shocks for the ZW7 Premium Ride suspension. Although I do not see many indications these shocks are bad (excessive roll and bounce), that is a lot of miles on them, and putting on more trail use will likely push them over. Plus, I am fairly certain this suspension was engineered for mostly highway use while towing a heavy trailer. Since I am going to replace the shocks, I might put fresh springs in, too. I decided not to go with the direct replacement of the springs but get a set for the Z71 package.
I did find a new set of reasonably inexpensive Moog equivalents for the Z71 springs that I purchased. I got a set of 81244 for the front and 81609 for the rear. From my research, I read this set is equivalent to the Z71 springs, and the 81609 is the one to use when replacing the Nivomat shocks of the ZW7 to standard. I could be wrong, so please shout out if anyone thinks I am going in the wrong direction. I know these springs are heavier duty and will likely give a more firm ride, and I think they may also give a bit more lift. I got these through Amazon, so I can easily return them if I am wrong.
Since I will have the Tahoe apart to do the shocks and springs, I might as well go ahead and replace the stock UCA and ball joint. I am not comfortable putting additional stress on the stock UCA/ball-joint, and from what I read, the OEM ball-joints are a bit on the weak side. The Bajakits UCA replacement is very nice, but it's on the expensive side. What are some alternative UCAs that everyone can suggest that will have similar qualities to the Bjakits? I don't think I need a UCA with the bolt-on replaceable ball-joint (Kryptonite, JBAOffroad...), but something not as expensive as Bajakits. I am not totally ruling out Bajakits, but I want to have some other options.
I decided that I eventually would like to put a 4" lift on the Tahoe, too (further down the trail). I like the BDS lift kit and will likely get the 4" kit that does not have the coil-overs. The kit without the coil-over has Fox shocks for the rears and uses the stock springs. They offer a strut with this set, but they are not Fox from what I can tell in their catalog. Further research on the Fox Web site shows they don't offer any struts (just shocks and CO). I also read that Fox shocks are fairly firm and designed for constant off-road use at moderate speeds. Honestly, I don't think I need a shock like that for my ride and for what I will be using: road and trail use. So, I am pursuing a different set of shocks as an alternative for the Fox that BDS has in this kit.
Right now, I am seriously considering the Bilstein 5100s. These shocks should work with the leveling kit I have on the Tahoe now and work with the new springs. The part I am unsure about is if these shocks will not work for when I do the 4" lift. I do know the shocks are ride height adjustable, but that is only for 0" to about 2" inch. I suppose I could use the spacers from the leveling kit if it seems the shocks will be too short for the 4" lift. Still, I really would not like to do that ( I could be wrong, but that seems like not the right thing to do). I would hate to invest in this set of shocks only to learn that they will not work when I eventually do the 4" lift. Can anyone say if the Bilstein 5100 will not work with a 4" lift?
