I was wondering....

All a spacer lift (such as Superlift's 2" lift) involves is replacing what's above the spring. Can't such a lift be installed by simply getting the JK up on jack stands, lowering the axle as much as possible, compressing the springs with a coil spring compressor, and installing the spacers without ever removing a single component from the vehicle?

I'm sure there must a be a good reason why it's not done this way, but I can't think of anything.

 

It takes a lot of time and patience to use spring compressors. It took me about 45 min to disconnect the sway bar, shock, drop the axle, and remove the spring to set my spacer in then put it back together. This was for both sides.

 

I have done it on a TJ by disconecting 1 side of the sway bar (no need for both) disconecting the shock, taking of the coil keeper and standing on the hub to fully articulate the axle down while some one poped the spring out. should be the same ish with the JK.

 

I just installed a FT 2" spacer lift this weekend. For the front you need to remove the spring anyway to install the bumpstop. Plus there are only 5 bolts to remove on the front, four on the back. If I hadn't had to open up a few holes we could have done the whole lift under an hour and a half.

 

I just added 2" spacers in the REAR to allow for heavy tire, and used spring compressors to remove the coils, then compressed them more after they were off (to allow for two more inches of space), then re-installed. Worked ok. The front has less space, so it may be a little trickier.
Good luck.