Thanks Howard. Unfortunately my Boulder gear is all balanced (no RCA's at all). I'd like to stay balanced entirely. I'm also concerned about mucking with the signal to my Sasha's as they sound entirely sweet, but need just a little help in the low end. Don't get me wrong, they'll play low, but there's low and then there's the low that a quality set of subs can put out.
Lots to think about. I feel like I've opened Pandora's box. I can see how this is going to end -- I just get fed up and buy a set of Maxx3's.