ATC Passive Speakers & McIntosh

I'm very interested in the ATC speakers, the smaller models SCM 20 and SCM 11 but I am concerned about power requirements. My MA-2275 puts out 75 watts, I thought that would be plenty and has been with my Klipsch's but the ATC's appear to really require a lot of wattage. I'm not going to get rid of my beloved MA-2275 so the question is should I just pass on the ATC's or is my concern warranted. BTW I was planning for the 20's for a large living room with high ceilings and the 11 for a 14 by 14 study. Your comments, experiences are appreciated.