The five speaker cable extension is a no brainer..16-4 speaker cable from Home Depot at $0.98 a foot added 20 feet for a total of 33' and no impedance or sound difference; works fine. Cut the factory cable in half, spliced in the 16-4 speaker wire (soldered each wire and shrink wrap each wire..don't want them touching each other!! Then shrink wrap the 4 wires together. Done.