Previously one of the owners wired the car for an aftermarket radio and presumably aftermarket speakers. They did not do too great of a job and as such, I am now undoing that.
I started off with the amplifier. You can see that they simply bypassed the amp and went directly to the sub. This isn't too big of a deal but I want everything back to stock.
After this I turned to the head unit. Frankly this entire wiring harness needs to be redone and it is on the list. As this is me writing from the future, I have received a full wiring harness and will be redoing that wiring back to stock before putting in a new head unit.
The car came with an aftermarket head unit, new in box. I also installed this at the time just to have something, but it ended up doing nothing of note expect making lights bluer and brighter in the cabin.
Tl;DR: I butt-spliced everything back to stock and fixed the few butt splices that were broken. This is all going to replaced in the future with a new wiring harness.