Your gonna have to go under the car and check the cables for the e-brake. Ther eis a grommet that the cable goes thru has been know to make that noise. In fact i bet in you garage, if you take the e brake off you wont hear it as much.
Give it a try
'11 128i M-Sport Pkg, Sport Susp., 6AT w/paddles, BMW Perf CAI,Charcoal Filter Delete, BMW Perf. Big Brake Kit, BMW Perf. Exhaust, Ferodo 2500's, Titanium shims,135 trunk lip, BMS-PBX Box-Map 3, Castrol RBF600 ,e93 FSB, , f30 Backing Plates,GC Camber Plates, Hankook RS-3's (Track setup)