Looking for some knowledgable help. Have recently pur a boat. Has 2 stock and 2 clarion marine speakers. The desk is a std auto stereo w/ CD, probably about 20 watts a channel. It cuts out at 25-28 on 50 scale volume wise. Looking at changing it out to add stereo, amp, and add some Infinitiy 6000 or Evid 6.2 on a yet to be installed tower. Looking for good, all purpase amp that will drive it all or do I need to go multi-amp set up. Runs with one car battery and one Blue Optima battery. Thoughts?