Here is the whole assembly all connected and in place. The silver box is the OEM door amplifier; the black box is the sub amplifier. It's tiny and cute. And powerful: 200w RMS @ 0.5 ohms.
Here are the two repinned Metra wiring harnesses (white plugs) connected to each other to pass signal through, and the Kicker harness (black plug) bridged off the L+/-, R+/-, (white and grey) and remote turn-on (blue). Other wires coming off the Kicker plug are power, ground, and output going to the sub.
Here is where my assembled harness connects to the OEM harness.
And here is where it connects to the door amplifier. You can see I also used other Metra harnesses to extend the door amplifier power and ground. I didn't tap off these at all, but I needed to make it longer in order to fit all the extra wiring.
