Don, installed Zimmerman front rotors on my son's 2005 BMW 745i recently. The rotors were high quality and were coated with a gray primer, just like rotors bought from a MB dealer. I would opt for the Zimmerman rotors.

There is no need to touch the wheel bearings. Simply remove the set screw and separate the rotor from the hub. You may have to pursuade the rotor with a hammer since they sometimes rust to the hub.

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Fred Hoelzle