Paul, welcome. My own listening is almost entirely classical and I've been enjoying great music through my M22s for over seven years now. I wonder why you place so much emphasis on "small"? For example, the M22s are about 6-7" higher than many "bookshelf" speakers, but are also narrower. Unless you have a strictly defined vertical space available, my suggestion is the M22s. The bass they provide is at least as extended as the M3s(enclosure tuning is actually a few Hz lower on the M22), but a boost in the upper bass around 100-150Hz on the M3 gives an impression of "fuller" bass, although it isn't quite as accurate.
The in-room response of my M22s gives usable bass down to about 40Hz, which is adequate for most classical music. However, if you listen to pipe organ or other very low frequency content no bookshelf speaker is going to handle that very well. I use the EP500 sub because of this. Although you've also emphasized no sub, if the budget would permit this should be considered in the future.
