Squeak is related to materials, very little else. A recurring squeak can be cured by changing the rotors and pads to OEM compounds, that’s Jurid pads in the front and Textar in the rear, a good Balo, ATE or Zimmerman rotor and 2 new caliper pins and the rubber bushing the pin rides in. Those pins and bushings can wear and cause the caliper to tilt and that is the likely cause if you are using the correct pads and rotors. BMW and TMD Friction spend hundreds of hours testing components to come up with the best blend. When consumers try to improve one area the result is a reduction in performance in another area.

Speaking from my experience, this is the best way to cure the problem, do not use any sprays or other snake oil when you install the pads, mount them dry and be 100% sure the pad shim is in place, that is your buffer between the brake pad “puck” and the caliper frame and piston. The shim will isolate the vibration to the rotor and pad friction surface and not let it transmit to the caliper where the squeak will develop.