For the wiring, you can just splice the remote wire into two. This is the best way to go about setting up remote. For the power, get a distribution block. Depending on what gauge your wiring is now, it may or may not be enough to power your new amp setup. The gauge and power wiring setup really depends on what amps ure using, and how much RMS your pushing. So its kinda hard to say. As for grounds, you can just make a new ground spot for your new amp. I think that pretty much covers it.