head unit power is nil when running amps. speaker wires run from amps and the signal is sent via rca's from the head unit to the amps. as for the brands of those amps or head units dont do it. get something reputable with ipod control. you can get a good alpine, kenwood, or panasonic for less than 200 in cali. or even on ebay for that matter.
I'm thinking you might be best off taking your boat in and having a professional install a system for you. That doesn't mean you'll have to spend an arm and a leg, it just means that the job will be done right, the first time, using quality components.. You really want the system to be balanced and wired correctly. Any professional audio installer will give you options either to go big or to be on a budget.. Just my .02 good luck..
A forum community dedicated to performance boat owners and enthusiasts. Come join the discussion about offshore racing, performance, modifications, builds, classifieds, troubleshooting, maintenance, and more!