I've been using the FOA 550 coils for a while now and they are the best I've tried so far. Period. No sagging, fading and good articulation with the ability to absorb pretty big hits. With MudChilds adapters and similar widening mods they were an easy install. I recommend trimming the longer 16" to fit since you'll have to cut at least 1/2 a coil off anyway to gain the pigtail you'll need for the control arm. Why use a spacer when a longer coil will ride better?, imo of course. Mine are longer than usual due to changing the angle of the lower mount so I can't suggest a finished length, you may need to adjust them more than once to get them perfect.