marine stereo

I have 4 kicker marine audio speakers and and Pioneer head unit powering them. It is plenty loud for me. Now I am upgrading and putting in tower speakers. I have 4 Polk MOMO MMC650's and I am looking for an amp I think I am going to go with the Kicker ZX450.2. If anybody has any opinions on this amp or suggestions for another I'm all ears. I have a couple of questions about the install... 1. Would it be better to install the amp in the side with the battery and have to run aproximately 20 ft of rca or mount on the head unit (drivers) side and run about 20 feet of power and ground wires. 2. Where should I mount, wall closest to the cabin or the one closest to the outside of the boat? 3. It is ok to run my cabin speakers through the head units power and just connect this amp to the head unit's rca's without having to change anything? Just hook up the rca's 4. Is there anyway I can hook this up to where I can fade all my music threw the tower speakers so I dont blow the people in the boat out? 5.What gauge power and speaker wire should I use. Any other suggestions or comments also welcome.

1. I would install it closer to the battery. The longer you have to run power cables, the thicker they need to be. Also, remember, you have to run ground back to your battery because the grounding block in your boat can handle that amount of current. 2. Not sure without seeing your boat. I've got a 25 foot Crownline I'm installing a bunch of stuff in and my amps are going in a storage area on a wood divider wall. 3. You can do that. I'm doing something similar. 4. Can't help you there. If your RCA outputs are fading then I would think you could fade your head unit to the rear and at least cutout your front speakers. Another option is to install a relay that you can wire to a switch on the dash. Flip the switch and shut off all your speakers in the boat except the tower speakers. I've got a relay to shut off my front speakers when we are on the beach. 5. I would think 4 awg would be sufficient. Just remember whatever you run for power, you need to run for ground as well. So if your amp is 10 feet from the battery then order 22 feet or so of 4 awg.