i think that's normal.
a few years ago, i posted a message that i accidentally pulled up on the e-brake while in motion and heard a horrendously loud "CLUNK" that was coming from the center console-armrest (and i could feel the vibration in the e-brake handle).
ChrisZang posted that i was completely normal (or that at least it happens to him as well)
so that makes 3. i'd believe it's a normal noise / sound.
http://986forum.com/forums/general-discussions/25193-help-please-brakes-ims.html