The stock alarm housing is under the steering wheel column to the left side like behind the hood release. There should be a little white knob sticking out of it. that adjusts the sensitivity of the alarm.
I just zipped tied my stock alarm box back up and it looks different than that. It has what looks to be the same connectors as a 20 pin ATX connector plugged into it and what looks the same as a +12 volt 4 power connector plugged into it.
They are both white and large enough to show up well, even in a blurry photo
ok it looks as though there is a hose on the left side of the unit for vacuum source, the large wires are for the ignition. The purple wire on the left side is probably for the o2 sensor or e-brake. The wires coming out on the right will go to the control box, follow those and report back.
No, people had already said that it might be various things, and the OP posted a few hours before I did saying that he still didn't know what it was. I merely stated that it looks identical to my TT control box, to reaffirm that for him.