I'm speaking out of my own experience ...Although recommended you do not need to go all out and do SYE on 4" of lift . My recommendation for a bolt on Spring under kit will be Rubicon Express RE5520m kit . 4.5" of lift and comes with EVERYTHING you need . Rides great , durable and doesnt sag . Well built quality product and you can fit 33" tires with no rub .
Rubicon Express Part RE5520M - 4.5 Inch Extreme-Duty Leaf Spring System with Mono Tube Shocks-RH1
I ran this same kit for about 10 years as a daily driver up and down I-95 and wheeled it off road with no sye or cv driveshaft , I used just the included degree shims and transfer case drop kit and it all worked fine . Now you can do it ,for and additional $600 in parts . If you dont want to go that high they offer other sized 4, 2.5 . But you know my standpoint