Thanks for the reply. I guess I could have been a little more specific. I guess it's less of a concern for actual space vs. visualized space, if that makes any sense. True, the stands would be the same. But I think the problem I'm having is that the Monitor 5's on my stands look huge...really, really tall. I bought the Premier s22 stands, as suggested by the monitor series site. (they suggest the s18 or the s22). In looking at the site, the Monitor 3's are actually 6" shorter, so that seems pretty substantial, especially when you're considering cubic inches, including the speakers depth and width. Floorstanders are out of the question as I just moved away from them, having sold some Boston CR95's. I like the smallness of the bookshelves.
At any rate, I think the sound is really more important, and as mentioned, you think the bass sounds a little tighter from the dual 6.5's. I do have a pretty serious sub (and SVS PB10-ISD) and crossover on my receiver is set at 80 Hz, so I wonder if that weighs into this discussion at all.
Thanks.