Pumping out that much SPL into even a large HT room will be an excruciating experience. You are right about the headroom for less efficient speakers though and you will likely never need another amp. Listening at 12 db SPL ABOVE reference should be a once in a lifetime experience. Let us know how it sounds.
Awesome, isn't it? Lmao! It may be a once in a lifetime thing because you may not hear much ever again after that lol. I want people to be afraid of touching my volume knob. I know I more then likely won't ever need that power, but just knowing I have all that power on reserve makes me feel good, and will certainly never have to worry about any material pushing my equipment too hard.
Honestly, I think this set-up would be able to power some professional movie theaters like clear view cinema's I've been to recently.