I already have one of the Titanic Mark II kits and now I'm thinking of adding another. If I stack 2 of the subs would that audibly increase the output? If I put one at each main speaker location would that increase the room effect problems? I've stuffed the sub with polyfil and like the tightness and punch since I listen to music, both 2 channel and DVD-A and SACD, more than movies. Just need some more output.