30X40' is a big room. How are your speakers currently positioned and your seating distance?
I think that if you're looking for higher SPLs, then the Midi might be a better option but if you're not looking for higher SPLs but rather a bit better bass extension and bass output, the 3.2s and sub combo (if it does indeed integrate well) might potentially be the most satisfying option. I've gone back and forth in terms of thinking whether a large speaker is better or having a well-integrated sub in the system. I still have not heard a big speaker produce the bass impact that I once heard a well-integrated Rel studio in a large room connected to an essentially full-range speaker.
I think that if you're looking for higher SPLs, then the Midi might be a better option but if you're not looking for higher SPLs but rather a bit better bass extension and bass output, the 3.2s and sub combo (if it does indeed integrate well) might potentially be the most satisfying option. I've gone back and forth in terms of thinking whether a large speaker is better or having a well-integrated sub in the system. I still have not heard a big speaker produce the bass impact that I once heard a well-integrated Rel studio in a large room connected to an essentially full-range speaker.