The CJ was first then that was improved a little with the YJ version in 87 both use leaf springs under the axle then again in 97 when the TJ was introduced.there are very few diffrences between the cj's and yjs. the most significant change was the use of coils in 97 on the TJ's they also started hvae a rear Dana 44 as an option and depending on if you plan to run larger than 33's would be something to look for. Those are the most noticable changes. good luck with your search.
2in body, TJ flares,32's, detriot true trac up front, powertrax no slip rear, mile marker winch, and more
400 big block, ford 9, dana 60, and some more lift