Should the rear shocks on a 2002 Camaro SS need replacing with only 19,000 miles on the car? I noticed that my car seemed to be bouncing more lately and is not as hard riding as it used to be. When I press on the rear bumper the car goes down and up 3-4 times before stopping; when doing the same to the front it only bounces once. Also is it normal for the rear suspension to squeak when going over a bump or road irregularity? I am guessing it is because my car has polyurethane bushings rather than rubber?