I used M30 motor mounts for 5 or 6 years. You have to hack off some little metal alignment tabs, but that's it. When I finally decided to spend the money on M42 mounts, I was glad that I did. The M30 mounts transmit a shit load of vibration & noise into the car. The M42 is a rough running motor, and the softer hydraulic mounts were used for a reason. It is unfortunate that they are so damn expensive though.