I just witnessed this kit being installed in the shop about 3 weeks ago. It didnt go on hard at all. Not in relativity at least. The kit prior to that was by Sierra Rock Control... if any of you are familiar with Ty and his company.
The maiden voyage was a jaunt out to the valley from Anchorage. I drove the jeep about an hour+ down the highway and into town, and through a couple hundred yards of bumpy, rutted, dirt "roads" to our annual Alaska 4x4 meet and greet event, where it flexed up quite well on the ramp. IIRC, on the 30 degree ramp, it scored somewhere in the 400-450 range, which is approximately 8-900 on a traditional ramp.
Ive spent quite a few hours behind the wheel of longarm'd jeeps from SRC, Rubicon Express, Full Traction, and others.
The full traction kit is hands down my favorite so far. It easily surpasses the other kits on the market right now in at least road manners. If anyone has yet to install a production XJLA kit from RE, you all know how ridiculously lousy the fitment is and how much modification it takes to fit the X-member to the XJ unibody. I lent a hand in that install as well about 3 monts ago. The Full Traction kit was a breeze in compairison, and is actually a bit cheaper than the RE setup. Not to mention, its a true 4 link, unlike the others, who mount there uppers to the lowers (aside from RK, who runs a 3 link). If you get a chance to see the Full Traction kit up close, take note of the HUGE heim joints on the end of the control arms, and also the flex joints at the opposite end.
Next XJ I own will have this kit.