I would imagine that using your factory control arms will be ok. The ones that I got with my 4" lift where only 1/2 inch longer. Either that, or you can get some adjustable lower, upper control arms, from Nth degree. You will probably want to lower your skid plate as well. The 4" kit comes with about a 1.5" shim. If you have a rubicon, you wont need to lower the skid plate, as you already have a SYE. They most probably offer this Kit as a very inexpensive lift. That would be my guess.