I ended up tapping into the door speakers (from the door) for the line out, put the amp in my trunk in the spare tire cavity, and then ran new lines to the door speakers. The rear speakers are faded out for now until I have time to wire them into the amp (I ran out of speaker wire the first time
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I pulled the tuner model, but was not confident that I could find the wires I was looking for, so I just took the easy route.
The kicker key is great and it makes my Rockford fostage 6x9 put out 3x as much bass as they were before. I don't feel the need to install a sub anymore. The auto tune took some trouble shooting, but I figured out after 4 or 5 tries.