Thank you very much for the reply. A couple of questions:
-What is BBK? If I don't have it any suggestion as to other brand name's rotor? I choose Brembo based on my research online, and price is reasonable. I mean the plain one Brembo, not the slotted one which is too expensive.
-Your car E39 looks like mine in terms of look. Is E39 a high performance 525 version? I am still learning more about BMW.
Those 4 shops said the same thing. They can't make money on the labor. They want to me to use their parts and labor, but the parts they offer are only OE or OEM, and they charge a lot even for OEM parts.