The door weatherstrip (not the window) has a design issue whereby it would be tear itself after a couple of year. However, this might be the only case for the earlier cars manufactured in 2012 which is the case of my BRZ.
I've ordered the weatherstrip, via the part number:
63571CA010 (WEATHER STRIP - BODY SIDE, FLANGE FRONT, LH) through the Local Dealer, to which the dealer had to order the parts from Japan. It only took the dealer to send over the parts from Japan after 2 months when I ordered it. I should have ordered the parts myself from Japan.
Anyways, there is a simple installation documentation on how to replace the weatherstrip.
Careful on where the place it was broken off (see the image where I was holding the rubber up), cause the part is only connected by a thin strip of rubber without any metal reinforcement on a 20mm width strip, whereas the all other parts is reinforced, making it a weak point. If it were to be left "free standing" without supports and pulled via gravity, you might start to damage it.
