I've made some progress. Particularly with the audio.
So, I had an old set of speakers laying around, and I was able to hook them up to the speakers that were mounted on the cab (a decent pair of 4ohm pioneer car speakers)

They sound great! the bass is kinda outshined now... but that's okay.
Here's the little control module:


It has an AUX and a Headphone jack, which means that I may consider this cab to double as a jukebox. We'll see about that though...
I was able to take the time to strip the cabinet down:

I also tested the power strip that they rigged up with an external switch: it and the Marquee light work great.



Okay, so now to the good stuff.
I need a graphics card with RCA (Yellow) out. This PC has PCI-e. It had a card with s-video, but the card is shot, and the warranty is expired, so I'm dead in the water on that.

Also, I'm looking for a router, i heard that the
M12VC is a good choice. I just don't want to shell out 200 for it and a bit set. Is it worth it? Know of a better deal?