I don't have any experience with RC but it looks
like a decent kit. At 4" it's a good idea to replace lower control arms, which this kit includes. You may also need to replace your driveshaft, depending on which one you have stock.
If you go with this kit I'd recommend a new steering stabilizer.
Here's a link to the kit for the lazy: http://www.roughcountry.com/jeep_wj_4x.html