Phil, the size of the listening room doesn't necessarily require a more powerful amp. Except in the unlikely event that your 525 would be distorting on peaks, in reality there would be no need for more power(and that special HK feature that automatically drops the volume 20% when it detects a wife entering the room is so neat!).Those people who've spoken of improved soundstage, detail, etc. with a separate amp may be deluding themselves. If they happened to set the volume slightly higher with the new amp, this higher volume in itself might improve those factors, but the same result would have been obtained by increasing the volume slightly with the old amp.
So, yes, unless the 525 is actually distorting, which you don't indicate, forget the separate amp and spend the money on those back surrounds which you can especially enjoy with Logic7.
