I am planning on upgrading my system with a 2000rms amp. I currently have single run of 4 gauge wire that is about 12 feet. Could I get enough power with another run of 4 gauge or should I pull it out and run 1/0 gauge wire? Its a spl car if that makes a difference.

Also, does anyone know the difference between wire found at a local hardware store (aka Home depot) and far more expensive installation kits? It sells for $2 a foot as opposed to $9+ from crutchfield.com. It would save a lot of money to use that instead.