Tree,
Check out
this article written by Alan (if you have not already done so).
It will give you an idea of just how much louder (or not so much louder) you could get just based on power specifications.
That being said, if you do play music at very loud levels and like to push the envelope, the more power will be beneficial in regards to the starting point for distortion. You should get a couple of decibels more cleanly with the separate components, but again, this would only occur at the very high end of SPL.
With my Onkyo 797, i have been able to hit the 103-104dB range (8' distance) with my M60s before distortion/clipping sets in. I would not recommend anyone listen to sounds at such levels, nor allow their components to drive their Axioms to such levels. If you really want more sound, you will need MUCH larger amps and bigger speakers.
