OHM impedance with sub woofers, which is louder?

Well theres two ways to look at it, Dual 2 ohm is a fairly popular/easy to run/hook up system, and is loud depending on the subs and amp you have, louder than dual 4. On the other hand Dual 4 ohm subs can wire to 1 ohm, and surp the dual 2 ohm subs. Now, if you decide to wire the dual 4's to 1 ohm, you have to make sure your amp is 1 ohm stable. Nearly all amps are 2/4 ohm stable, but not all are 1 ohm stable, so if you dont feel like doing your research on which amps you could wire 1 ohm to, then i would say your best bet is dual 2, being louder than dual 4.