amp question

I'm adding up all the costs that I'm going to incur for purchasing a new boat, and trying to figure out the best stereo set-up and costs involved. I'm going to most likely run four 6-1/2 speakers in the boat and 4 6x9's on the tower, and I'm thinking of kicker speakers all around, and possibly an L7 sub. Would I be ok running two amps for this set-up, 1 for the internal speakers and sub, and one for the tower speakers? I'm thinking either Soundstream or Phoenix Gold amps, which models of each would be recommended to get good sound w/o totally breaking the bank? Thanks in advance for the input!!!