I had the Teraflex LA upgrade installed last spring and have been very pleased with it. Good things always heard about the RK kit as well. Some buddies just installed a Synergy 3.5" long arm on a 2dr and are over the moon with the quality and how well it installed. So, pick your poison. Just bear in mind they're a bit of work to install, mostly involving the cutting & grinding of the old mounts, tank removal, welding on new mounts, etc. Need a well equipped place to work, cutting torch, grinding eqpt, and quite a bit of time. I ended up farming my install out because it was just beyond what I thought I could do in my garage.
'09 JKRU. 4" Teraflex long arm, Teraflex R44 housing, Teraflex / Fox Resis, Poly Performance skids, Nemesis Billy Rockers, Nemesis flares, 37" ATZ P3s on 17" 5x5.5" Trailready HDs, Spyntec hubs, Teraflex BBK, Mopar BBK master/booster, Superior front & Alloy USA rear axle shafts, CTMs, Reids, Synergy drag link & tie rod, WTOR hydro-boosted steering, 5.38s, TF Dual Rate front bar, TF bumpers, Warn Powerplant, Tom Woods shafts, AA xfer case cable, Kilby canister relo, RH4x4 cage.