My son wanted rear speakers put in our 99 cherokee which did not come with the rear speaker setup. I first got a stock radio which had the rear speaker setup. I went to the junkyard and got 3 speakers and the rear wiring out of a 2000 for $10.00. The hookup for the rear speaker wiring is there in the 99. It is just hooked out of the way behind the right rear plastic across from the spare/. I made a wooden template for the covey hole ,cut two holes for speakers and hooked them up. I did not go for the roof mount as I did not want to spend the money or time with the fiberglass set up out of the junkyard jeep.

 

Here's how I got rear speakers. I mounted them on top of my subwoofer rack I built. They angle a bit forward and sound great!