Patrick, welcome. You'll be delighted with your M22s, and no, you won't "need" to replace your PSW10. As you know, however, although the PSW10 has fair response down to about 35Hz, there are many subs which will play at a higher level and will reach considerably deeper. If you decide in the future that you want this, you can consider a replacement, but it isn't urgent to do so now.

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Enjoy the music, not the equipment.