Joseph, welcome. It would be unlikely that you'll be able to find worthwhile info on an M2/532 comparison. A meaningful comparison would be at the same place, same time, same music material, played at the same sound level, etc. It's unlikely that you'll find someone who's done this.
I'll suggest that with the height restriction that you've specified, the M2 should be an ideal choice when combined with that good sub. If you haven't studied it before, you should check the M2
SoundStage review and NRC measurements .
I'll also suggest that the very broad dispersion of the QS4s would make it the superior choice for the surrounds.
Another point is if that bookshelf placement is absolutely necessary, try to have the front edges of the speakers at least flush with the front edge of the shelf rather than recessed, to minimize reflections and refractions.
