Made my own "kit".
Hand cut new grooves on a set of FX4 front shocks to lower the spring seat 1.25"
Had the rear springs re-arched by 3"at a local spring shop. Used 3 1/8" spring perches, new 2 1/2" u-bolts and a set of Jeep spring plates to flip the axle. With the new spring plates on top of original spring perches, used the u-bolts to dial in <.5 degrees of pinion angle and locked the axle into place.
Added a pair of early 2000's Nisan Frontier Rancho RS9000 shocks with Amazon sourced 14mm x 16mm aluminum tube cut to 40mm for the bushing mounts.
Final result was a bit low in back, used a set of Amazon sourced 1" lift spring shackles for the final rear height
Replaced the OEM foam bump stops with 600 lbs/in Timbren rubber springs spaced about 1" above the upper spring plate.
Set the Rancho's to max stiffness setting and am VERY pleased with ride and stance. OEM spring rates, the FX4 front shocks soften the front harshness and the Rancho's keep the back end under control.
OEM FX4 rear springs have a lot more arch than 2/4 WD springs and might be an option for the needed 2.5" - 3" "lift"needed for the axle flip.