First post yall! Love the site but my moomba even more.

Got a question for ya electronic fellas. Im totally ignorant when it comes to stereos, amps and speakers so i need all the help i can get. Lol. Im replacing my amp and not sure what i need. I have 2 kicker single barrel tower speakers, I forget model but I think they are 100watt each maybe 150. Also 4 kicker 6inch speakers inside boat. A buddy told me i needed around 1000watt 6 channel amp but they are very expensive and hard to find. Id like to stay with kicker brand and was curious if the 5channel XFM700.5 (i think) would be sufficient. Im really wanting to keep cost under $400, so if ya can please help.