So I guess the big question is it all worth it for either a stock lift height or mild(2-3" lift)lifted height LJ? so..................
Take a look at what I have done thus far here:
You're kinda losing me on your "little or no lift" stance when you then mention 3" here in a lifted LJ. My rig has 3" AEV/Nth springs in it that are old and sagged a bit. I just finished my 3/4 link build for the most part, just wrapping up some loose ends and fine tuning things.
What I know thus far on my LJ is this was ABSOLUTELY worth every bit of work. I didn't label it the "bump and grind" for nothing however. I had damaged every bit of factory suspension brackets, mounts, etc. under the rig. I had damaged body mounts as well. Pretty much all factory suspension parts have been removed and I built my own in addition to the body mounts due to being too low to the ground. All my skids have been beat as well and while there, I did the gas tank tuck even further than what I already had.
All that said, look at what I did to make the suspension work with such a short spring. I wanted a 12" travel shock with at least 6" up and I got it but it wasn't exactly an "easy" or "fast" thing to get done. In addition to what I cut in the rear, I also had to cut/notch my front truss to clear the track bar mount and the oil pan and had to cut out part of the factory engine mount at the frame. My upper link is literally just below the AC compressor now at full stuff. I'm not sure how much further one could go without just going full custom and totally relocating the engine as well. I already have a 1.25" BL and 1" MML on.
The handling of the rig is hands down worlds different than it ever has been before on any prior suspension spring/shock combo I've run. Wayne's custom tune on the Fox shocks is nothing short of amazing. In addition to the greatly improved highway ride, total loss of body roll I'd been fighting all these years and have hated thus far in life, probably the biggest change I see now is the handling over rough washboard roads. I have hated washboard roads to date with a passion as they just beat the hell out of the rig. Now, I'm grinning ear to ear and mashing the pedal down just to see how fast and how firm the rig will go over them. Before, I'd constantly break the back end loose at speeds up to 25-30 mph and that was IF I could get that fast. I'd loose traction, spin tires and fish tail in addition to getting beat to death. Now, I haven't lost traction at all with the new setup yet on the same roads, haven't spun the tires and haven't fish tailed or broke the back end loose. The rig is firmly planted to the washboard yet soaking up the hits like they aren't even there. edit- to add at speeds over twice what I was doing before.
From my learning thus far, I would say it is absolutely worth while to go this far with a rig BUT you'll need to find and address exactly how much lift you want and how much shock you expect to get out of it. I'm not so sure I'm going to keep my 3" AEV springs now as I'm not real fond of the amount of drop out I have in the rear with the 12" shock. Should you decide to run a shorter 10" shock, you'd be OK with that I'd think on this height of lift but wouldn't have the travel I have with the 12's. The Currie 4" spring is well known to work well with the 12" shock travel and keep things seated at full droop and I'm seriously thinking of just going to them. It will likely change my shock travel a bit and I'll likely wind up with a bit more up than I have now but I could easily cut the lower axle mount and re-weld it a bit higher up then dial everything in from there. Other option to keep it low is cut the spring perch out and set them higher in the frame so even though it is still a 4" spring, it is set higher and thus giving a lower stance similar to what I have now, to keep the springs fully seated on the 12" shock at full droop. If you haven't gathered yet, it isn't "one" thing in general, it is the combined sum of the whole together that makes the greatest difference. The shocks however were the biggest hitter I think in my opinion.
I'm not sure what the whole "LCOG" thing is really these days. Seems everyone has their own idea. Everything on my rig is tucked as far as I can go with it without totally re-inventing the wheel and eliminating the tub yet I would never call it a "LCOG" build.
Figure out what travel you want and how much up you expect and go from there. My rig is in your 3" range but with the travel I have, I may be eventually switching to 4" springs to keep them seated at full extension with a 12" shock. Time will tell.
Best of Luck,