From what I understand...the magnaride uses the ride height sensors to determine voltage at each shock valve that the magnetic fluid (Ferro fluid) moves through. So if your torsion bars were cranked up or down, or changed out... or you installed aftermarket hubs or control arms. Any of that....then your z height up front could be off. In that case you would have to recalibrate the pcm bump stop and ride sensors using a MDI or equivalent. The idea is you don't want the control module to think much if anything has changed from stock geometry-wise And there are other factors like shock length, are you using blocks on top of rear axle..etc ..etc.I have a 2005 and I just use a VCX Nano for GM. No need to SPS update...but I would see if there are any updates for your pcm, bcm or suspension control module. I know that's sounds a bit technical and my wording isn't exact from the manual. All the necessary info should be in the sticky. I'm sure others who have more experience will chime in. Can you list your changes from stock?