I have searched 20 pages but I just can't find the answer! I have a pioneer head unit and I have the trim out of the rear of the cab so thought it would be a good time to upgrade the speakers from the facory infinity units. I need to know which wires are the 'speaker' wires as there are 4 (in a multiplug) and if i can even do this keeping the front infinities for the time being? help much apreciated!