Hey guys.... I see a lot of Exile questions here so I'll chime in.
Generally speaking I like to break down the stereo into 3 distinct zones. CABIN / SUB / TOWER. It sometimes gets complicated when planning upgrades and sorting into an existing setup. First and foremost you need to establish in your own mind, what you like and what you dont in your system. Yes, we can guide you, and we probably can quickly guess what you'll like and dont about your system, but ultimately this input needs to come from you.
My take would be the following. And this could be based on upgrades over the long term, and not just an total system redo.
CABIN ZONE - The Exile 65's + existing 4 Channel amplifier would probably be just fine. Yes this amplifier has ILS ratings (ILS = If Lightning Strikes) but I'm fairly certain it will be adequate to properly power the cabin speakers.
SUB ZONE - The JL SUB and JL amplifier are a good fit together. I'd keep this in play and not change a thing.
TOWER ZONE - This is where it gets tricky. Because you really should consider moving these Infinity speakers onto their own amplifier. I have a hunch when you do that, and get some time out on the water, you will still be looking at upgrading them into something that is more performance oriented.
Since we dont know about the budget... I'd just suggest a short term amplifier upgrade and then a longer term new tower speaker upgrade. Here's a this year / next year plan.
Infinity towers + XI800.4 ; then next year dump the Infinities (they will be blown by then) and drop a pair of XM7 / or SXT65
If you'd like some visual help on all these zones, shoot me an email to firstname.lastname@example.org
and we can get our marine Powerflow system guide and it lays all these zones out with pictures. You can insert the models/brands that your setup has to help you organize the future plan.
Lastly, you mentioned this is a new boat (to you). I'd suggest getting out on the water and seeing what you really like and don't before contemplating lots of changes. If you have done this...cool. If not, turn up the volume and see how she does
ps: Bendow>>>> Did you ever put that BIG15 in your boat? How'd your upgrades ever turn out?