So now, power wire gauge question, the amp has a max of 117W on 4 channels. That is 468W. P=I*V, so I=P/V. Substituting values, I=468W/12V= 39A. Multiply this by a safety/loss factor of 1.5, you get 59A. Ampacity of 6 gauge wire is 65A at 86°F or 49A at 122°F.
So, 6 gauge should work, but 4...