Factory Sub Retrofit

[Lurp]

I was at the local Pick-n-Pull on Saturday where they'd just put out an '03 4.4i, and while grabbing the parts I was actually there for, noticed that the poor 'ol girl had a factory sub. 3 easily removed fasteners and a bit of haggling later, it was mine for $15. Now what?

There are a few things I know going in: My X5 doesn't have DSP, a sub amp, or any of the associated wiring. I've also read several posts here and elsewhere suggesting that the factory sub (if you can call a couple of 6" drivers in a plastic box a "sub") ain't much to write home about. That said, it's better than what I have (nothing), and I wasn't budgeting any coin for a worthy alternative any time soon.

My current plan is to purchase a Chinesey sub amp on ePay for ~$15 and follow this excellent write-up about how to add a sub here on the forum. Alternatively, I could run wires from the sub output of my Eonon deck, but I'd rather have a root canal than pull up the interior again. Unfortunately, that post isn't written from the perspective of someone installing the factory box. So, there are a few things I'm hoping someone can tell me about the factory sub:

1. Does anyone have a wiring diagram? I clipped the harness with the connector, but there are more wires than I'd expect for a passive box.
2. Should both drivers fire in unison? In opposition? Is one a passive radiator perhaps? (I can remove them for inspection to answer the latter easily enough).
3. Any idea what their intended power handling is?

Knowing that, I think I can pull off a factory sub install for ~$30