Hey Wayne,
While I completely approve of new speaker build projects, I know for a fact a pair of sealed subs do wonders for those speakers. While I would love a pair of servo subs, I settled (for now) for 2 SVS SB2000 subs. I bought one a long time ago, and another a year or two later. I have them tuned to be pretty close to flat down to 20 (+3ish down low actually) which means keeping them really low volume but letting them smooth everything and pick up underneath. If you wanted to check it out before you sell your set, just let me know. I'm just up in Vancouver. I know my system isn't perfect, but it could give you a taste of Studios & Subs.
-Lloyd