I am in the process of adding aftermarket speakers, 6-channel amp, and subwoofer to the factory HU (LX-S with standard 160-watt radio, non-Nav). Will be running a Scosche HA10B from the wiring harness to a Metra 71-1722 harness plugged into the OEM radio. A PAC SOEM-4 will be used to provide the RCAs for the amp. My question is this: which wires do I connect on the Scosche to the Metra? I realize that the HU will need power, accessory, ground, and illumination. Should I connect the speaker wires from the Scosche to the speaker wires on the Metra or should the Scosche speaker wires be left unconnected to the speaker wires on the Metra and connect the Metra speaker wires to the speaker wires on the SOEM-4?

Any other suggestions or alternative wiring options are appreciated as this is the only alternative to not cutting the factory harnesses that I have been able to find. The PAC AOEM HON20 apparently will not work for 2010 models (per PAC techs).

Thanks in advance for the suggestions.