Rich, if you want to "enhance" your HT, you're discussing about the least likely candidate to do so, i.e., adding even more amplification. You presently have what's in effect a bi-amping setup, with the sub amp handling the low bass and the 1906 amp handling the frequencies above that. Unless you presently aren't able to play at maximum safe(to your hearing)sound levels, which is highly unlikely, adding more maximum power capacity would be meaningless; unused headroom is simply that: unused. This is audio fact rather than fantasy(e.g., some of that quote from the S&V writer).
Speakers are generally the way to enhance HT performance, and looking specifically at your list, adding QS surrounds appear to be the logical candidates for this.
