I got a 4 door 88 Cherokee with ripped up front seats, there power seats and was wondering if I could swap in a newer grand Cherokee seats?

 

I believe that the ZJ seats will fit. I know that you can take WJ seats and fit them to later, 2001, rails.
I was looking for a set for my XJ and thought that I had bought a set of ZJ seats from a local recycler. Turned out that I got WJ, 2004, leather seats. The doner vehicle had been t-boned seriously on the passenger side so the right hand seat is pretty mashed.
The seat that I bought were fully featured memory seats with heat and all the bells and whisles. I have a 2001 XJ Sport with manual seats. So some work was required.
The WJ seats just un-bolt from the rails and bolt directly to my XJ rails. Now they are thicker as they have much better padding than the basic cloth seat that I had. I am 6'3" so it was a consideration but the seat is great and I am not bouncing my heat off the roof.
One consideration was how to deal with the power/memory seat. I used the manual rails in my XJ so the front to back is the same as it was with the old seat, the challenge was how to deal with the power seat back and reclining.
I got a hold of the wiring diagrams and all the rest of stuff that relates to the memory system for the Grand Cherokee 04 but after looking at it decided that trying to use anything from the harness was not going to work. So I bought a momentary dtdp switch and wired the recliner motor to it. Wired it to the 20 amp outlet in the dash reusing connectors and wire from the harness.
The seat has full heat and I am going to look at using those circuits in the future.
I bought the mashed passenger seat so that I would have a matching seat cover if I found another good seat. In looking at how everything is the same frame wise beteween my cheapie cloth seats and the loaded power seats I am going to see if I can just switch the frames and use my manual passenger seat with the leather power seat foam and cover.
My total cost for the upgrade was $149 tax in for the two seats ($100 for the driver's, $25 for the passenger's plus HST) and $12 for the switch.

 

I already got power seats and already leather but I want newer ones, so should they just bolt up to the old rails?

 

Alright I'll see if I can find some, I was just wondering if I would have to drill holes or anything like that

 

The 04s WJs that I got bolted directly to the bolts on my XJ 01 rails, no holes, not mods just unbolt and bolt on.
Since you already have the power rails I would think that you would be way ahead of me!

Good luck.

 

Can't be too much different from a o1 to a 88 on seat rails right?