I've done it. In reality, you get about 2.5" out of the rears and almost nothing out of the front. To remedy this, I put a set of 2" spacers on top of the springs in the front. Even then, I still have a decent forward rake since I have no backseat and a winch on the front bumper. In order to get the rear springs to fit, you need to cut off about 1.5" from the bottom of the spring. It looks almost like the tail of a pig... Also, the shocks will work, but you might need a bar pin eliminator, or you can push the bushings out of your current shocks and into the JK ones. In short, if they're free, do it. If someone wants to sell them to you for anything over $100, it really isn't worth the trouble. I also had 150k miles on the factory shocks and springs and they needed to be replaced badly.
Remember that when you change the height of the vehicle you raise the center of gravity which can effect the speed at which rollover occurs.
It's funny, when I installed the JK springs on my LJ, I got the same response. So I gained 2.5" on the back and someone said "Oh your CG is going to be off", Umm why not go tell that to the guys running a 6" lift kits? 2.5" is like raising a Jeep 2 thumb widths higher, in a Vehicle that already HAS a high center of gravity. Maybe some people drive their Jeeps like Ferrari's but I always KNEW that it will never handle like a sports car, what makes people think that since I lifted it I'm going to try and take corners FASTER? I just don't get why when anyone talks about putting JK springs and shocks on this CG convo comes up!
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