Installed it myself on the previous rig. Our intent was to gain the extra 2" rather than an alignment correction. We got what we intended in that regard, but we really struggled to get the rig back into alignment afterwards. Every attempt we made created a different alignment issue, until we found a happy medium. My conclusion was that it is not as user-friendly of a system on older rigs that have short spring hangers.
Like I said, we got the extra 2" which is what we wanted. We were more than displeased with the quality of hardware. There was more than one bolt/nut that we torqued to the instructed specifications and it stripped the threads. It also made our rig less stable side-to-side.