Re: Speaker opinions
x3 on the Polks. I just did mine a year ago. I bumped up to the Polk 6x9's though. Got 4 display units from an Ebay auction nice 'n cheap. I didn't see much reason to stick with original 6 1/2 rounds. It took me 10 minutes with a jigsaw to oval out the holes a little bit to 6x9....I suggest you consider doing the same as it will give you a smidge more bass than the 6.5" rounds. Most boats have PLENTY of room to upsize a bit. With my 22 watt rms head unit, and no amp, it is PLENTY at cruising speeds. The bass is surprisingly adequate...better than I expected. It's not a thumper obviously, but as a 40 year old male I don't really need or want the people across the entire lake to hear me pounding along...at only 1/2 volume it is far louder than you can have a conversation with, and it sounds good. Rarely do we crank it up that high unless we're sitting in party cove and a jamb tune comes on...
My #1 recommendation while doing this:
REWIRE. EVERYTHING.
Pull new speaker wires, pull a new hot and ground wire directly from the battery with in-line fuse...do NOT run it thru the boat's fuse block (voltage drop issues on most 11-year-old boat factory wiring cause static and sub-par sound.)
FWIW, I thought my 1999 boat had a blown speaker too. And it did. So I replaced the speaker and it still sounded like junk. That's when the ohm meter came out for some testing, and I found my speaker wiring to be substantially and surprisingly corroded with high resistance, plus I had inadequate grounds and undersized wire all-around. 14 gauge is IMO a good size for most everything on a normal powered setup...and most boats are built with 18 gauge for the stereo and speakers...inadequate for the length of runs IMO, ESPECIALLY as corrosion sets in with age, and resistance goes thru the roof. And when rewriting, get proper sized crimp connectors and the tools to install them. NO TWIST AND TAPE...EVER!! It'll never last in a boat.
REWIRE EVERYTHING while you are doing any speaker or stereo work. So easy, so inexpensive, so frequently overlooked, and yet so critical...ESPECIALLY ON BOATS. You will be glad you did.