4 15s if given the proper air space would be louder then 2 18s, in almost any setup. Two 3500d.1 strapped at 2 ohms wouldn't require any more batteries then what you listed, if you wanted better then 13 volts full tilt you would need 4-5 d3100s or more alt output.
Thanks for the help!! What if I wanted to push that setup and be a little louder would FI Bls be able to handle that power at .5 ohms
I have seen BL 10s handle 2500 on music so I don't see why not.
Alright thats good to hear. Thanks for the help now I know who I can ask for help and advice lol.
No prob, and here is fritos honda with two bl 10s on addictive 5k, each seeing around 2500.
http://www.youtube.com/watch?v=gaz_cNajE-Q
Hmmm ppl always told me to never push the BL over 2K