My electrical is a 250 alt and 400ah almost of batteries total. I have enough room for 2 15s if I did beefy ones or I could do a single 18. I am open to any brand really, my budget for now is set on around 600. What setup would you do? Looking to do half ohm to see what it is difference wise. Any suggestions? I have a box for 2 15's that is 7 cubic feet after all displacements tuned to 35ish with 2 XFL 15s. Not really any goals in particular, just louder with better subs. I am open to used or new.