Right now I have a 4 gauge wire running from my battery to a 500W amp in the trunk. I am adding components and want to add another 500W amp under my driver's seat. The current power wire goes right by there so I figured it would be an easy addition as long as I have a distribution block. I have one but it only accepts one 4 gauge wire and put out two 8 gauge wires. The block would go under my drivers seat. Would it be safe to run 8 gauge from that point to my amp in the trunk and the amp under my seat or do I need to run 4 gauge to both?