What's the best way to get the sag out of my 89 without compromising ride quality? I would think some lift shackles would do the trick, maybe blocks. Only need to go up about 2".
I did 2" SHORT add a leaves. My total cost was around $57. The leaves were $37, the new longer u-bolts were about $20.
It wound up making the rear about an inch higher than the front.
If you did LONG leaves, by say Rancho (they make a 2" kit), you wouldn't really feel much of a ride comfort difference. Shackles are fine, but I wouldn't use blocks.
My 2" short leaves did stiffen the ride, and in the summers I keep the top off and the rear is a bit stiff. It is because they are short and thick and have little give. The difference in ride is minor though.
The zuk mod is the way to go, just really do your homework and examine the amount of sag you have because if you over do it with the zuk, the truck will look ridiculously high in the rear. I've seen some bad results around the internet. Its a matter of getting the right spring rate, and possibly cutting the springs once.
The Zuk is worth it though in regards to articulation. Unfortunately there are tons of how-to's and people using all different types of springs from donor trucks or black magic, so really take your time, check your height and do your homework.
If you are just leveling the rear back up with the front you cannot go wrong with either a shackle lift (@ 2"), a long leaf add a leaf kit, or the Zuk.