Honestly, the slam is more than enough in this configuation. I've already confirmed 6 dB more output here and love the way it sounds (much better than I thought it would). With my room, that corner placement seems to work very well. It's a starting point, and if I get bored I may play around some more with placement, but this seems to work. I've also considered running them in "stereo" up front. But this stack really appeals to me. These things are sick man! Just sick. I think they as a pair are a Conquest killer, and much better looking.
The reason I now have two is because one just was not enough in my living space. I found that I was actually pushing my single Ultra to audible distress (if you can imagine that). I estimate with my great room/kitchen that I am looking at nearly 5000 cu ft.