Most of your questions have been answered in messages here - I'd refer you to the messages but maybe if you try the search they might pop up.

You are correct about the rear speakers - both signal and power leads to them. There's a really good thread on that which is, I believe, this message: https://www.crossfireforum.org/forum...ead.php?t=9308

As for the factory amp and speakers, you have many options.

I wired my aftermarket head unit into the car using a harness connector that goes onto the aftermarket head unit.

Then for my mid and high-range rear speakers I used the aftermarket head-unit speaker-level outputs. For my sub, I used the aftermarket head-unit sub-output.

The sub has an integrated amp so I also connected the remote power on lead from the aftermarket head unit.

I left the factory amp to power the front and rear factory speakers. They all run out of the "front" channel of the aftermarket (and factory) head unit so I can do front and rear balance.

The side door speakers benefit from installing a crossover which is also covered here though many aftermarket head units have high-pass filters settings that can be used to accomplish much the same thing if you isolate those speakers in your wiring plan.


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