rpk, I would agree 100% with mla on the sub choice. I had jl 12w6's in my supra and first tige and LOVED that sub. the current boat has a 13w7 in it and it's friggin massive, eats up most of the storage under the jockey box and weighs as much as a teenager. frankly I'd swap it for a 12w6 if I knew someone that would so i could get it back under the helm.
12w6 is a pretty easy sub to stuff under the helm and at the party cove, we rocked pretty hard using an arc audio amp in a sealed box. iirc it was a ks1200.1