[barelyinaudible]

yea, getting into speaker arrays is a whole mess of technical info... let me ask you this though, what impedance are your speakers wired to? if they're at 8ohms, you would probably get more results just dropping your speakers down to 4ohms (provided your speakers and amp can handle the difference) and just keep the gear as it is...

i usually try to drop the speaker load as low as the amps can possibly handle before i consider increasing the power of the amp. most live sound amplifiers are pulling the same amount of juice weather you're pushing them to max or not (i am a live sound guy, so feel free to correct me if car amps don't work this way, though i would assume they do.)

sometimes dropping the load can increase the output by almost double... you should also make sure your crossover network can handle the increased load, you don't want to blow up any capacitors now... that's never fun.

100 amps is a TON of current... sounds to me like that would result in alot of wasted juice. for example, i can run 3 600W(RMS) amplifiers in the room i work on a 20A fuse without much fear of exploding anything (though there was this one time... i won't get into that.) i have run these amps through the ringer at 4 ohms on most channels and still have yet to blow the fuse.

750W should only be pulling about 6-7A from 120V, at least from what i remember...

you should be able to pull a considerable thump from the fit's stock battery, it's just a matter of setting it up right.

[edit: i know dropping the speakers' impedance obliterates headroom, but a good crossover can easily keep the headroom shortage to a minimum.... lesson here: CROSSOVERS MAKE OR BREAK THE SYSTEM.]