Never used anti-squeal goop myself. Never needed to. I did, however, switch my brakes from the OEM to ceramic to get rid of the brake dust. I bought one of the kits from
bimmerzone.com. I called them up and had them switch in Akebono ceramic pads for the standard OEM pads (at an extra cost of $40 or so). Total came to $400 to my door for front and rear pads and rotors (and sensors). Installed them with some help from a couple local enthusiasts in an afternoon. All good to go.
Almost no brake dust now, less initial bite on the brakes (but I hated that anyway). The new pads are 10x smoother than OEM brakes, and I'd say about 90% of the stopping power. No complaints.