Could someone please go over the evolution of the AR 11/12" woofer from the AR1, AR3, 9, 10, 11, and any drop in replacements that were offered over the years? What's currently available new, is there a new AB tech 11/12", is it identical to any of the production units? I would think that the AR303a woofer will not fit the other designs because it does not have the side cuts, correct? There are some T&S measurements on this site I believe? I'll try to find that thread.