I assume my car has original speaker wires that are connected to my front and rear speakers. Do I need to buy new speaker wires or I can use the originals? Also does it make a big difference to buy 14 gauge speaker wires from crutchfield for better performance or it really makes no difference? Also to connect a 4 channel amp to power do I need to buy one power cable? I'm seeing only for 2 channel amps and it says for 4 channel you need to buy additional cables.