I purchased a used Infiniti M35 from another dealer. About a month into ownership, the brakes were shuddering. Took it to Infiniti of Valencia. They said that in addition to the brakes, the driver's chair was coming lose from the frame of the vehicle, the drive belts where broken and just flapping around inside, and fan shroud was broken. This would cost me $2,400 to fix. I didn't have that kind of money and so I had them fix the brakes only. I took the vehicle to a non-dealership mechanic. He agreed that the fan shroud was lose, but he took out the drive belts and showed me that they were not broken at all, just a bit cracked--they definitely wouldn't have been "flapping around". He also said that he could find nothing wrong with the driver's seat.
Will not be taking my vehicle back to Infiniti of Valencia, even though there is no other Infiniti dealership in my area.