Ditto what SD said. For all the work/frame butchery that would go into a coil conversion on a YJ, you'd be WAY ahead to trade up to a TJ.
One more point- A panhard bar (or track bar) does nothing to eliminate axle wrap. It locates the axle side-to-side under the Jeep. A lot of guys new to Jeeping are reading this- let's be sure our answers are accurate.
Corona <img src="/forums/images/graemlins/cheers.gif" alt="" />

'98 TJ, 4 cyl., auto
31" AT KO's on rockcrawlers,
custom bumpers, Hellas
2" Teraflex lift, no top,
no doors, no problem.