No firsthand experience with the Rockcrawler, but I am in love with the Teraflex Long Arm Elite kits. You can get the 4" or 6". They handle like a dream on and off-road and the quality of the components are second to none. Almost all the guys I trail with are running Teraflex suspensions and they perform awesome. The kits are comprehensive too - everything's included.

BIG to Teraflex!