These are Delrin, and fall in between poly and solid metal as far as stiffness goes. The mounts are available as total kits, front and pass side, or as individual front and side mounts. Delrin, like some poly versions, requires some break in time. It will take 150-250 miles for them to soften to their effective hardness. They also require some heat in them to soften up. And on colder days they may have more vibration at start up until driven on for a few miles. They are also self lubricating so they will never squeak.
The Stage II mounts are designed for pure performance, at the expense of ride comfort. They will hold the motor and transmission very securely and help get all the power to the ground. If you drag race or are after total performance, then the Stage II is for you. If you are concerned about vibration, then the Stage I, or .5 are a better choice. Upgraded hardware is included with all kits. FITS ALL MKIII 2.0, VR6, VR6 Corrado