If your shock travel is long enough you can unseat a coil. So it really isn't a matter of the spacer per say, but how much travel you have in your shock. I see more of a problem in the front than in the rear. If you are using OME springs with a spacer and the OME LT shocks you can easily unseat the springs. There are spring clips that you can get from Jeep to clamp the bottom coil of the spring to the axle spring pad. If the suspension is set up correctly you won't have any problems with it. I have RE 3.5 springs on mine with the LT shocks. I can unseat the springs from the upper isolator and reseat them with no problems as the suspension flexes.