Our polyurethane rear trailing arm bushings are designed to replace your failing, rotted, OEM rubber bushings.  They install into the existing bushing shells.  "Trailing Arm Bushings" is something of a misnomer.  The bushings install in the rear axle housing!  We provide detailed, step by step, fully illustrated instructions.  These bushings come with a lifetime guarantee.  If you have done your torque rod bushings, changed your rear shocks and you are still hearing clunking from the back of your car, your trailing arm bushings could be the cause.  Replace them with urethane!  $110 per set, does both sides of the rear axle.  $10 shipping via Priority Flat Rate Box in the Continental U.S.