I just this minute finished doing it on a '92, if that helps.
Took me about 4 hrs, but 3 of those were spent fitting the switches. I completely re-fabbed the switch mounts so they look stockish and placed them next to the rear defroster switch. Lots of dremel and xacto work. (pics later today after the sun comes up).
If I had left the switch mounts alone and used them out of the box I would have had to mount them under the dash and I have that space on both sides of the steering column reserved for GPS, radio, and my knees. But it would have only taken me about an hour to do the job.
Overall it was quite easy. Getting the gauge module out was a snap. I am still waiting on my factory service manual to be delivered, but I used the Chilton's and it was accurate.
I used the indiglo style gauges, they have a tab on each face that needed to be folded over the edge of the existing face.
Contrary to the instructions (they said I only needed to do this if I were removing the needles, and I didn't plan on doing that) I warmed up the Jeep and let it idle for about 10 minutes, then I recorded all of the gauge positions for reference later. That actually turned out to be a good thing, I had to re-align one gauge after installation. It must have gotten tweaked and I didn't notice.
Also contrary to the instructions, I found I did have to remove the face mounting screws before installation, for a clean flat fit. They went right back in no problem. Before you tighten them down, align the face well. It helped me to put the gauge bezel back over the faces temporarily to help align them.
Be real careful about the needles, this page may help:
http://www.seas.ucla.edu/~cheston/IndigloGauge/indigloinstall.html
Slide the center hole of the gauge face over the long part of the needle. As the hole nears the center of the needle, push it down against the faceplate to slide the center hole under the center of the needle so the hole will fit over the back (short) side of the needle.
I used cyanoacrylate adhesive (superglue stuff, this particular brand is made for r/c hobbyists) instead of double-sided tape to tack down the new faces where necessary. Tape would probably worked just as well.
I removed all of the lamps except the turn signals and bright headlamp indicator, and replaced their sockets in the holes -- all but one close to the center. That hole I used to route the wires for the gauge faces.
I dry-fit the gauge module back in the dash after the install, but I left the clear plastic lens and gauge bezel off, in case wiring or needles needed re-work.
I had to re-align the voltage gauge after installation. All the others were fine. I just started the Jeep, let it warm up and compared the readings to those I took before the install. Then I pushed the gauge needle to the right spot and all is well.
I re-assembled everything and now its late. But it looks kewl.
If I can do it, anybody can.