You don’t need the more expensive Dualcore for two subs. The 8033 will happily equalize two or even four subs, but only in mono. That, however, many would argue is the best way to connect subs anyway. See here for connection examples of the various 8033 models:
http://www.dspeaker.com/en/technology/anti-mode-technology/anti-mode-connection-examples.shtml
http://www.dspeaker.com/en/technology/anti-mode-technology/anti-mode-connection-examples.shtml