Hanz, another welcome. Sure, when your budget permits, a reasonable second step would be getting M60 mains and moving the M3s to surround duty. If you want a center speaker later it'd be more important to have a close match there with the mains, so an M2 might be a better choice than an M3. Then, still later, if you want to expand to 7.1, it's suggested that you use the wide dispersion QSs for side surrounds, rather than a direct radiating speaker(moving the M3s to the back surround duties).

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Enjoy the music, not the equipment.