^^^ Adam and I could be "those guys" at the sandbar (and usually are lol). You'll listen to what we want to. Adam's 15" Arc sub is stupid deep with the gains turned down even. Interstate SRM29 are probably the most common batteries out there and are super reliable and inexpensive. I have 3 of them. Also you might want to look into an onboard charger if you are going with a 3 battery set up. Don't rely on your alternator to maintain your batteries. You need to get a charger that puts you right at or very close to 10% of your total amp hours to be able to desulfate your batteries if ran down. Adam and I went overkill on our onboard chargers. I have a ProMariner Pro Nautic 50 amp. I believe Adam has a large Xantrex. Some people rely on Battery Ternders which is fine for a topped off battery but not to desulfate them. This is what I have
http://www.anchorexpress.com/promariner ... AulB8P8HAQBy far the most popular is this and I had a couple and they work just fine
http://www.anchorexpress.com/ProMariner ... Aks08P8HAQ