Definately go with the KP rear bolt-on 4 link and cantilever. They give you an awesome ride, 12 inches of travel, insane sides, and they're a true direct bolt-on kit. I've installed over 15 of them, with truck laying anywhere from 18's - 23's on their kits, and never had a problem. They come complete with all the mounting harware, detailed instructions, shocks, and they're powdercoated for years of duribility.
Check out their site for more information
www.kpcomponents.com