They guy on benzworld knew what he was doing. If I were you I would find a shop that knows superchargers and tell them to do it for you. You should be able to buy the rebuild kit from eaton, but if you dont know what you are doing then get someone who does. As for the size, there is a right and wrong size and shape. He did it that way to have the edges of the outlet to match with the tips of the rotors at 180 degrees ensuring a perfect seal and maximum efficiency.