OK, i'll try and clear it up.
I currently have in my truck: jbl1200.1 & SX12
I currently have in my boat: hifonics zx6000 600rms & (NO SUB)
Im just looking for a sub for my boat, and i dont really have much room for 2. And i dont want to underpower another SX, or spend the money for an SX and have it get wet.