Any lift for the KK that does not include new brake lines and a adjustable(or longer) rear trackbar shoild not be used.
The stock brake lines are barely long enough for the stock suspension,adding any lift will stretch the brakes lines and they can and will fail,re-routing of the rear ABS sensor lines in needed also.
Myself and RockLizard have test fitted a Frankinlift on a KK and at full droop with the stock suspension the brake lines were about as tight as bango springs.Also without a adjustable rear trackbar(or longer one) the rear axle will be shifted to one side after lifting.
JBA is working on a 4"(and 2.5") lift for the KK that will be complete,not cheap but it will be complete with all needed parts,just waiting and the rear brake lines and we'll be test fitting one on a KK sometime real soon.