Both of you look at the search bar. This same discussion has been gone over ad nauseam. This is a very common discussion and has been extensively explained. Someone, although i can't remember who had even posted a table showing what components are required at what amount of lift as well as what tires they will clear. If you are confused when a manufacturer for example says that a specific lift kit will clear 33x12.5x15 tires and you want the metric equivalent 305/75/R15 google a metric tire converter it will clarify things. Now as far as your question, yes a steering stabilizer is required, but that is a given, they have to be replaced at specific intervals because they don't have an indefinite lifespan. Now IMHO the rough country lift kit is not worth the money. It isn't particularly expensive but it's crap. Look at IRO lift kits, they have more quality kits with better components in the kit.
However keep in mind, (and this is why you want to use the search bar) that there is more to lifting a WJ than just a lift kit. Right now I'm at 3" of lift with components I pieced together from various manufacturers. I'm running a 31" General Grabber AT2 tire. I'm planning on getting rid of all of it and going up to the IRO 6.5 Long arm kit. I'm looking to run the BFG M/T KM2 in a 33". It's gonna be big bucks because of the regearing, axle swaps, drive shaft swaps, SYE, and the like. Most of those are necessary components to lift it that high. Now do you need all of those things at 4", no but I wanted to explain that you can't just slap on a 4" "lift kit" and be done with it. So check around on the forum and see what others have already done.