So--I bought my M3 with 104k miles on it. It now has 109k. The previous owner definitely neglected the car. When I got it, the brake light was on--it turns out that the PO had gotten a brake job and not had the sensors changed. My guess is that it was a Midas brake job or something.

Anyway, they replaced the wear sensors and said the pads and rotors were fine. At 107k my brakes started squealing fairly loudly. I do not ride my brakes, and did not race the car or anything. I took it into a BMW dealer and they have told me the pads and rotors are glazed and I need to replace them. The rear alone were quoted at $370 (employee price as I work for the company that owns the dealership).

Can I just replace the pads myself? They said there was plenty of life left on them. Should I try sanding the pads and rotors?

Thanks!