Try adding anti-squeal paste to the contact points of the anti-rattle clip, that seemed to quiet my brakes up. I did this while replacing brake pads and rotors though, so I'm not 100% sure that's what fixed the problem.

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2003 530i, Silver on Grey, BC Coilovers, Square 9.5" M-Parallels, Gloss Black Roof
2007 328i, Alpine White on Black, Sport/Nav/Premium
SOLD: 2006 X5 4.8is, Lemans Blue on Black