Kelly, welcome back. As Mark pointed out, any difference in sound that you may notice if you take the M3s to the dealer may be due to the different room or some other factor in his setup. You can be confident that the VSX-01txh won't add any audible coloration, since it's a typically well-designed modern unit that amplifies transparently within its designed power limits. In other words, from that standpoint, there's no benefit in taking your M3s to the dealer to listen.

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Enjoy the music, not the equipment.