It's funny you mention this.....I just bought a set of sachs sporting shocks and an Eibach pro-kit. The sachs were sitting in a guys garage never installed for years. I recieved them and the fronts seem to be in good shape. The rears don't seem to rebound quickly like the fronts and I am not sure if they should be that way or not. Some people tell me they are dead others tell me they are ok. They took me forever to find and I am unsure if I should install them or not. I do know somebody who is selling a set of the front shocks if you are are interested in parting it all together. Did you ever compress the rear shocks before installation and notice the rebound time. The fronts are done within seconds and my rears take about a minute.