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.
The general advice for SCM20 would be at least 100 watts into 8 ohms. You are wise to be concerned and if you like to listen at realistic levels then you will probably be disappointed.
Are you still you using stock KT88s?
Yes, everything is stock. Because of the power demands I am now leaning towards Tyler Acoustics mainly because someone with ATC's recommended them. Is this an apples for oranges comparison?