I've never heard or read a positive opinion on RockKrawler lift kits.
Three thousand bucks is a lot to pay for a lift kit.
Another thousand or more will be needed for SYE and steering upgrades, exhaust, etc.
Using all sperical rod-end style joints will contribute to lots of road noise.
Using solid stock for suspension arms is an engineering cop-out.
The added stress on the uni-body from track bar drop bracket and drop pitman arm is not addresses in this kit.
I don't believe their add copy. In particular, the comments on bump steer, anti-dive and un-matched climbing ability.
The inter-leaf friction of leaf springs helps dampen body roll. Changing to coils while at the same time increasing CG without addressing roll center height sounds like a good way to create instability.
Supporting the rear of an XJ by the shock mounts is questionable.