I guess I'll throw my 1 1/4 cents in, adjusted for inflation.
I bought my XJ with Rough Country springs, front and rear, with 4.5" of lift. The springs were pretty sagged out. Who knows what brand of shocks. The Jeep was extremely unstable; swayed a great deal off highway. Pretty much had to run a sway bar up front on the road.
1st step, replaced the shocks with some used ProComp 9000 given to me by a friend. It helped a bit, but not anywhere near what I needed.
2nd step, replaced front and rear springs with Rough Country again; new in front, 1000 miles old in the rear. Also replaced the ProComps with 12" Bilstein 5150s, front and rear, in 255/70 valving. This made a significant difference in slow speed crawling. Great flex (new control arms, drop brackets, shackle relocation as well), much less sway. At this point, the sway bars went away, and highway manners were reasonable. However, higher speed in the whoops was limited to about 10-15 mph. My test bed was the road heading north off Means Dry lake, toward Lower Big Johnson.
3rd step, replaced a cracked rear main leaf, and sagged out right spring with a pair of used RE springs graciously given to me by a friend at the last minute. Much stiffer spring, probably 5.5" lift. Also replaced 5150s with Bilstein 7100s. 12" short bodies in front 400/100 valving. 10" short bodies in back with 360/80 valving, 10" due to new axle and higher mounts. Sway on the highway is virtually gone, ride quality has not diminished. In slow speed, I still have just as much flex as before, but I get much less body roll as the wheels traverse uneven terrain. The higher speed stuff I now can take at 25-35mph. Still no race car, but fast enough for what I need.
4th step? Who knows? I want to get actual weights of the axles, and try and determine the best spring rates. I feel I need a bit more spring in front, but the back feels about right. On the really hard hits, I hit the bumpstops in the rear, but not excessively. In the front, I am hitting the bumps more than I'd like. But I think the shock valving is pretty close.
Before I hear that my valving is too high, and I would have tended to agree initially, realize that Gomer is one heavy pig. Winch bumper, Powerplant winch, ugly heavy rear bumper, plated frame, belly pan that weighs a thousand pounds, 241 T-case, Black Box, tons of junk in back. I've never weighed it, but it would surprise me to come in at over 5,000 pounds.
So, as expensive as 7100s are, they offer a great deal of flexibility. When I got my 5150s, I was convinced I would never, ever need to spend more than $100 a shock. Even that price was hard for me to fathom. But, to get the higher valving rates, you don't have much choice. The 5165s may be a good alternative also, since you don't have to change out the shock mounts to run them. If you're just doing occasional high speed stuff, for short periods of time, you don't necessarily need the fade resistance of the 7100s. Though, I must say, on a particularly quick romp through Death Valley last year, I did get the reservoirs pretty warm on the 7100s.
Each rig will be slightly different. Weight of the vehicle, intended primary use, etc. Bottom line is go with whatever shock will give you the dampening you need for your application. Cal was correct, even heavier springs for higher speed will still work well for the slow crawling stuff. $185 for 7100s; $175 for 5165s; $75 for 5100s. How many times do you want to replace shocks as you improve your rig?
David Bricker / SYR
