FWIW, I would go with "more than necessary" amplification, to the extent that it's possible...I have S2's (ribbon, but not EX) as my L/R currently, and "recently" upgraded from an "integrated amp/receiver" to separates, including 400 W/ch D-sonic...it's dramatic, and I now understand review terms like "air", "effortless", "sing"...my S2's (not EX's...yet) are my main L/R and the 400 w/ch really lets them do what they do best without "working"...can't wait to get towers and "relegate" the S2's to surround duty....