I got mine here its a pretty nice amp. Its a refurb but it does come with a birth sheet if that matters lol. $195 Shipped is not bad.
http://cgi.ebay.com/KICKER-KX650-4-ZX650-4-CAR-AUDIO-4CH-SUB-AMP-AMPLIFIER_W0QQitemZ130218009466QQihZ003QQcategoryZ39739QQrdZ1QQssPageNameZWD1VQQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247
I dont know but its 120x4 at 4ohms but the 650.4 amp is underrated mine says 719 watts:veryhapp:how come on the kx it doesnt give the 4ohm specs?