Well... After setting everything back to zero, I started the car. The noise was still there. But something cool happened. When I turned the car off, but kept the radio on, the noise went away. I had absolutely NO NOISE. No crackling, just pour nice sound. So.... Tomorrow, I'll try a different grounding spot for the amps. I have a bunch of wire and connectors. What's the smallest gauge wire you'd use for a homemade ground wire?

Thanks again, Will.