So my rear shocks are not as perky as they used to be. They don't spring back up like they used to. The front is fine, it pops back up quick but not to fast. I'm just wondering what I can do. I have the stock shocks that came on the old ultimate. Do I need to just buy new shocks? I have read that people put different kinds of oil in them. What does that do? I'm not a racer just a basher so don't have to have anything crazy but would like to keep the back end off the ground with out too much preload.