My brother's been thinkin for a long time and searched and He's finally decided on the RE Audio XXX. He chose these because the JL 13W7 seems like it's quieter and can't handle an insane amount of abuse like the RE XXX. He has a Rockford Fosgate 1500.1bd amplifer that says it's not 1 ohm stable but he had 2 Alpine Type R 10's running at 1 ohm but he doesn't what to run it a any lower ohms than 1 and it's 2003 model so they aren't in stores anymore. Here's the question, should he get 2 12's or 1 15. The 12's would be running at .5 ohm, could fry the amp, or 3 ohm, under powering the subwoofers and getting less boom. The 15 would be running at 1 ohm.