Try re bedding them. It's helps a a lot with these pads. Mine were toast after two years on my old 330ci. I too had a lot of metallic noise with those pads and zimmerman rotors. I recall actually like those cheaper akembono pads over the HP.
Cause ^iggaz styles are old like MachRc's sneakers. Lyrics are weak, like clock radio speakers.
Don't even stop in my station and attack. While your plan failed, hit the rail, like amtrak..