Man, I want to say, I'm incredibly frustrated and at the same time having an incredibly good time. Kinda feel like a teen again.
The case where I have to use the OEM headunit. I've spent a
lot of time researching and think I'm close. Going to take some harnesses from
Ali Express and some splitting but I "think" it will work. Along with an old mapping picture I found of the "brown" block, I think I'll have my left/right forward/rear knocked out. I now know what LOC's are. (yeah, I'm that basic). Never used them back in the day, just good old RCA outs. I mean, how much cost would it add to have car makers just do RCA's? Oh well, that would be too easy.
So, I'm chasing my teenage dream of my JL 3 ohm 8's. Doesn't seem like they have DVC 3ohms anymore. Kinda makes the SVC 3ohms hard to deal with (not impossible). I know there are options, but challenges there as well. I want matching amps and the ideal state, doesn't give me matching amps. Oh well, more research.
So, I'm at here as of now.
Get that Ali Express harness, rip out the brown 8 way block (left front, right front, left rear, right great) and either
a. LOC and/or DSP and feed it to two dumb amps or
b. get a DSP Amp and have that DSP Amp feed a dumb sub amp.
Leaning towards a for the matching amps.
Then deciding if I have the patience and time (and money) for a 3way front stage).
Thanks again all, you have been super helpful!!!!!
EDIT: Oh yeah, a challenge I still have is a damn center speaker channel from the OEM head unit I can't track down at all. Don't know where it is coming from and how (or if) I can turn it off without affecting the other components in the car.