I did this upgrade on my '92 a number of years ago.
I found that my truck wasn't pre-wired for it, so I built my own harness using the wiring schematics from my FSM and connectors I got from someone parting out an XJ going to the JY, it wasn't difficult. I also bought an OEM switch and put it in the stock location. I got power from somewhere near the fuse panel (not in the doors), but exactly where escapes me presently. Whole thing looks factory-installed since I even hit up a JY for the little flat panels to replace where my "joysticks" once were.
The worst part of the job was getting the harness laid under the carpet, but at the time I had that out to deal with a leaky cowl, which made it a lot easier.
Anak - I can't think of any reason why the 97+ mirrors wouldn't work for you. There's no fancy computer circuitry involved - just two motors (one for up-down, one for left-right) to actuate the glass, and a switch that allows each motor to be sent 12V in one of two polarities. if your truck is already set up with wiring, I'd guess the worst part electrically would be changing the connectors on the new mirrors to match them up with the older harness in the vehicle. JY connectors, wiring diagrams, and a few splice connectors are really all you need for that.
TRCM's already covered fitting the mirrors to the doors, but there are other writeups around here from the past that you might find interesting, have a search around and I'm sure you'll turn up a couple...