One thing I just considered...
If I go with the M2Ti's for my mains (see prev post), will I "run out" of speaker when I move into a bigger place in 5 or 6 years?

Or could/would that be a problem with either one?

I think I just answered my own question...

Yes whip, it could be a problem with either, since they appear to be fairly similar in dynamic capacity. Unless the place is really big and the level is really high,however, I don't think it would be a problem with a sub relieving them of much of the bass production burden.