X3
It all depends on what you want to accomplish. IMHO, the best donor for an '88 Comanche would be an '88 Cherokee, with the same engine and transmission, because that will provide the maximum number of replacement parts. However, if your goal is to update a Renix-era Comanche to completely new running gear and electrics, then the '98-'99 XJ is probably the best choice.
I am in planning/researching process for updating my 87 mj & was curious. Why not the 00-01?