I have searched around but not found mating connectors for say:
to plug into and use the in car wires to the speakers, and or the power supply / turn on signal to an aftermarket amp.

The worst case is that I remove the PCB mounted connectors from my amp and use them to make adapters, or i have to cut/solder or tap into each wire back in the trunk.
Same goes for the connections to an aftermarket head unit up front.

Am I missing something, I am not yet talking about the Parrot or steering wheel interfaces.

Pete