Package HELP!

Sup pimps, ok, so my friend has infinity speakers powered by a rockford, u dont need the specs, and an alipine HU, but anyway, he wants a sub/amp/box combo if possible for 300$. He doesnt mind at all to loose SQ for SPL, so whatever is the loudest for under that, any ideas?? He said a audiobahn 600 watt rms, with some amp, and i was sure that their is something louder then that. Whatever is the loudest for under that price, 1 12, 2 12's, or whatever. Let me know asap, thanks!

well, he'll need to build his own box to keep it under 300. audiobahn gets loud for cheap, but he will definitely loose alot of sq. maybe a shiva with a well made ported box. and with 500 watts.....that will give some nice bass

tell your friend to save up