Tommy, welcome. The combination of the M22s and PB12+ is excellent and not in need of changing. Yes, get the QS8s for the surrounds for ideal spaciousness needed in that function.

If you have the room to vertically position another M22 for a center speaker, that's highly recommended, but there should be no concern whatever about using the VP160. The horizontal dispersion and mid-range/treble is very similar to the M22.

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Enjoy the music, not the equipment.