Welcome!
I took my KK offroad the second day i had it, the first day it had already gotten dark and there is a curfew on our trails. Also had a lift, rims, tires and some other minor things on it before I got real license plates for it.
I have the JBA 4" and i can tell you that it could cause stress to your CVs and any other front end parts, but any lift will put more stress on it really. with the fronts being adjustable you can set them to a height that you feel is safer for your front end. also the rear springs that are now coming with the kit yield about 4.5-4.75" in the rear. The springs that came with it before gave about 3" and you could always request those from Marlin at JeepinbyAl, im sure he could help you out. Also just read, word on the street is that there is a new OME suspension available for KKs overseas so its just a matter of time before its available here. Well see what comes of that though!