I'm gonna reinforce that power wire today. In the mean time, here is the wiring into the head unit I did on Friday.
You can pull out the wiring harness to make it easier on yourself to sit in the passenger seat while soldering. I cut the wires above the harness (i.e. between the harness and the head unit). I soldered the wires from the head unit into the LOC wires and the speaker wires into the wiring harness, which goes out to the rest of the car. You'll have to strip back some of the black cloth wrap to get at the wires.
Here are the eight wires you need to cut-- it's the four brown and four white ones near my thumb. Note there are other brown and white wires in the harness, but it's those eight together that are the speaker wires. Glad I did my due diligence before I started snipping.
From another thread, here are the wire colors with the pin numbers:
24: LR- brown w/yellow stripe
25: LR+ brown w/green stripe
26: RF- white w/orange stripe
27: RF+ white w/purple stripe
36: LF+ white
37: LF- white w/brown stripe
38: RR+ brown w/white stripe
39: RR- brown w/blue stripe
I soldered the wires together end-to-end. Took me a few hours, but here is the finished product. Looks like a damn mess, but it works. Once I got one of the channels wired up, I turned the car on to test and see if the whole system was working, which, much to my elation, it was. Then I finished the other three channels up.