I recently built a winch bumper and with the stock springs the front end of my 96 XJ  4L was sagging. I picked up a used  set of  front springs from an ZJ that had a V8. Installed them and almost got 2.5" of lift. Wow! The job was  reasonably easy to do, used lots of penetrating oil and I saved a ton of money buying used. Went for a road test and the front end no longer feels mushy it's awesome.
I priced new springs    160.00 $
                Used    "            30.00 $
All the best
Gman