Wet sounds 808's or JL 7.7's

Are the Wet sounds xs808's or JL 7.7's worth getting over 6.5's?

I have a basic system in my boat right now with 4 jl audio tr650 and the stock clarion 6.5 in the bow powered by an 400 watt 4 channel amp. I don't have a sub or tower speakers.

I was thinking of putting one of the sets of JL's in the bow and buying an 8" coax in the rear speaker location. I am hoping to get a little more bass with out adding a sub. I also realize that 8" speakers won't take the place of a deicent sub with 500+ watts going to it.