When I had my 08 2 door I ran a Rubicon Express 3.5 lift. I used the RK spring wedges to take the bow out of the rear coils. On my 2012 unlimited I'm thinking of the 3.5 max travel. On the max travel the rear arms locate the axle 1 inch farther back. The lift also comes with the coil wedges, but with the lengthened arms does this pose a problem with the rear coils bowing? Any side view pics of the rear coils after the install would be appreciated.

 

They do bow. Use the wedges provided and hose clamps as spring retainers and you should be good.

 

I have the 3.5" max travel on my 2012 JKU Rubicon. I don't have a side view, but here are a couple of pics. The springs are bowed, but not significanlty and it doesn't impact suspension performance.

 

They will bow a little bit, but with the wedges in its not enough to impact the performance of the suspension.