Ok, I just went through this unexpected PITA on my 90 XJ with 2" spacer pucks. I'll give you some advice that'll hopefully help. The bumpstop extensions are not removable, as far as I know. I searched countless forums, and there were some great write ups, but all the advice was different. Here it is in a few steps:
1. You will need one, better if two, jacks and a good selection of SAE and metric sockets and open end wrenches. Most of the SAE were 1/2, 9/16, and 3/4. I think one 18 or 19 mm, and a smaller one. You'll need a set of jackstands that can hold your rig. Some guys said I wouldn't need coil spring compressor, but I tried without it and failed. Got the STRUT SPRING COMPRESSOR from Pep Boys for free rental. It saved the day. The regular coil spring compressor doesn't work, as you already know. The strut one clamps the coils on the outside of the spring. Wear safety glasses.
2. Jack up the jeep on one side under the front bolt of the lower control arm or axle tube and remove the wheel. Put at least one jack stand underneath for safety. Also, completely remove the sway bar end link, shock absorber, and unbolt the tie rod end. If you remove the sway bar entirely, it will make it even easier, but not necessary. Remove the coil spring retainer clip. It's threaded into the spring perch, so it just unbolts and comes off. It strips easy, so don't over tighten it when putting it back on.
3. Now, with spring somewhat compressed naturally by the jacked up axle and all the in-the-way stuff disconnected, put the Strut Spring Compressor clamps on the spring. Follow tool instructions carefully, as this could be dangerous if the tool is not used as instructed. Tighten them down, but you don't have to overkill it, since the spring is already compressed some.
4. Here's the fun part. Jack up jeep on same side, under the frame rail close to the front upper control arm or directly under the upper control arm rear bolt. Put a jackstand next to the jack for safety. Jack it up pretty high, if you can.
5. Remove the jackstand under the axle and lower the axle jack slowly. The axle will begin to droop. Nice articulation with all that stuff disco'd.
As the axle drops, the spring will stay compressed because of the strut tool spring clamps holding it together and will begin to "slide down" the bump stop tube. Hopefully, enough to (a) put the spacer in above it, and (b) enough so you can get it out.
6. Now the funnest part. You will have to wrestle the spring off the perch. It's nerve racking with the clamps on it, as it doesn't go out easily. I found that it came out easiest through the opening on the inside-rear corner. Put the clamped spring assembly somewhere away from you or loved ones. You're on the 10 yard line now.
7. Put the new spacer on the bump stop tube. There's usually a flat spot on the side of the spacer, which faces towards the inside of the fender. You can leave your existing upper coil spring isolator on or take it off. The spacer can be installed without it. My OE ones were tatered, so I put new ones on first with the 2" spacers underneath. You might want to put some grease on the spacer where it meets the isolator and the cupped portion that the spring will sit in. This will help prevent squeaking.
8. Wrestle the clamped spring back on. You might need a helper to hold the spacer up, as the spacer tended to slide down. Make sure the bottom end of the spring is seated properly in the lower perch.
9. Jack the front axle back up again until the spring is seated properly in the new upper spacer. Put a jackstand under the axle for safety. Loosen the spring clamps on the spring. It will expand into the upper and lower seats. Remove the spring clamps when loose enough.
10. Put back on the sway bar end link, shock absorber, spring retainer clip, and reconnect the tie rod end. Put wheel back on. Torque all bolts as specified by your Jeep Service Manual. Remove jackstands and lower the jacks. Touchdown!
That's the first half. Drink a beer at half time, and go do the other side in the same manner. Don't skimp on removing stuff that I mentioned. It takes minutes to remove those parts, including the sway bar, but will take 10x longer if you try to leave them and work around them. Plus make wrestling the spring out more dangerous. PM me if you get stuck.
