John, it appears that the question is based on a misconception that the M22s somehow would need a sub to match the M3s in the low bass area. This simply isn't true; the NRC measurements show that the M22s have at least as much bass extension and in fact the low point of the impedance curve in the bass is a few dB lower in the M22s, indicating that the enclosure tuning is in reality slightly lower. The impression of more "fullness" in the bass of the M3s is due to an elevated response in the upper bass around 100-150Hz, followed by a small lower midrange depression. The M22s have more "real" bass. The VX-10 is of course a relatively inexpensive sub, but it would extend both the M3s and the M22s a bit more into the lower bass area. If only the M22s were paired with the VX-10, it would of course increase the small edge which they already have in the low bass area.
The M22 reviews which you mentioned bear no relation to reality; the M22s are extremely accurate reproducers and my use of them, often without a sub, resulted in adequate bass for most music(even most classical music which I listen to has almost nothing below about 40Hz, and in my room the M22s alone have usable, but much reduced output at 40Hz). For over a year now I've been enjoying the EP500 with my M22s, which has benefited pipe organ and other classical music which does have significant content in the very low bass and of course is also helpful with the occasional LFE content that appears in movies.
