Looking to upgrade the speakers on my boat. And am wondering if I really need marine speakers? I'm assuming it would make sense! I'm looking at some kicker 6.5" km6200 any one had these? Any other reccomdations would be great! I'm just looking for a good loud clear system and am looking for 4 speakers and an amp. As of now I'm not gonna get a sub. My boat is an 18' mariah shabah