Contact Summit and verify the manufacture of the optical sensor. If Mitsubishi, it's probably a good item that they're stamping their own name and parts (housing, cap/rotor, etc... via economies of scale) on to profit off of vs. the OEM unit. If not Mitsubishi, be very particular and dogged about asking who's making it, what upper RPM it's rated at and what assurances come w/ it. Many lesser OS's have emerged in recent years which can't handle the same RPM's the Mitsubishi unit can and soon thereafter fail.
i sell optis and you can ceom to my house and i will show you how to do it..