In this huge room and these crazy volumes, you should definitely look at external amps and maybe for more than 2 ch. The typical contenders for relatively low cost amps are offerings from Emotiva (XPA2, XPA5) and Outlaw (monoblocks).
Enjoy your speakers wile you can cause pretty soon you won't be able to listen to them wink

Bruno
M80s/VP180/QS8s/EP600/AVR-890
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"The problem is choice..."