Complete rear engine mount with stock rubber and metal bushing removed, and replaced with 70 or 88 durometer solid urethane bushings, For the Mazda 3 and the Mazdaspeed 3. Improves driveline response by inhibiting driveling lash, putting all that motion to the task of moving the car along. After the rubber from new stock mounts, we weld in strengthening pieces and then powder coat the metal black. We then install the solid urethane bushings. The 70 durometer bushings, which are recommended for the street. The 88 durometer bushings, which are only recommended for racing. These are too hard for the street and will cause an undesirable resonance in the car. For street applications, order the mounts with the 70 durometer bushings.