OK my 05 C6 was lowered and i loved it it was done before I got it so I am not sure what was done. I know the mono spring has adjusters on each end that go under the control arms and they can be adjusted. The car had a knocking noise and it was because one of the rubber mounts on the adjusters was worn out. My shop said they could not find the rubber piece so the entire spring needed to be replaced!! :lookinup: They are a good shop so if they said it was so it was so. But now it sits about 1.5 inches above where it did. My guy said the new spring had much thicker rubber on the adjusters and this was why. I am going to run the car for a few weeks to see if it settles down. Had anyone had experience with this? Where the thin rubber adjusters after market and the thick ones stock? Does anyone know who I can ask?