Try this setup, I think the JBL is the better amp but the JL has the better crossover in it. I'm not liking its 800 watt rating with the engine off (12V) because as a concert engineer I don' like underpowering loudspeakers. Let me know if you have any questions. Good Luck!

Thanks for the diagram. Will be waiting for Santa to deliver Amp

What do you guys think about Cadence stuff? I don't think thety have any marine applications though. But right now my Jeep is completely wired with Cadence stuff, other than the Kenwood headunit and the Kenwood Sirius tuner. But everything from the speakers, to the cap, amp, and subs is all Cadence.

Here's a good read on different speaker wiring and impedence values.
http://www.termpro.com/articles/spkrz.html

I would advise using 2 MTX amps. Also use heavy guage wire to power them. MTX rates their amps honestly. A 240 w. amp. may blow away a 400 watt other brand amp. I ran a pair of 12's MTX 6000 thunders with an mtx 240 amp and it was incredibly, rediculous powerful.