Neither the HK nor any other competently engineered receiver has a "sound", Dermott, so there's no need to worry about a match between receiver and speakers. As far as the speaker question itself, if you're going to be using them without a sub you might possibly prefer the M3 because of better bass, although it also has a bit of a hump in the upper bass. This, and a following slight depression in the mid-range gives it an impression of greater fullness , although the M2 is a little more accurate.
