Rears don't take as much abuse as the fronts. I usually run the second from the cheapest shoes. All will have a "lifetime warranty" anyways and will probably outlive the Jeep.
If you are looking for more stopping power, then a Disc Brake conversion would be best. Google for XJ Disc(k) Brake Conversion. It's been done many many times.
Get the $35 shoes and enjoy. There is usually a $10 "core charge" on the old ones. Don't let your wife throw them away the next day when you are at work. lol