I remember reading your posts before, but why don't you just go with a VP100/V150? I mean, rather than trying to use Axiom bookshelves as centers and being disapointed in their sound, why not just go with a true Axiom center? It sounds like I'm being a smart***, but I really don't mean it that way at all. I'm just curious of your reasons *not* to go with a center-specific speaker.
As if I have room to talk: I'm using M22's as rear surrounds....
To your question, I suspect that an email to Axiom would yield the best results. Perhaps Alan will be along to explain why you're getting exaggerated frequency responses with the M3's. Alan knows all.