Well, I don't pretend to be real knowledgeable about this, bit I think the size of the cabinet has a direct effect on a speaker's performance (frequency response?). So, if you put the M60's drivers into an M40 cabinet, it wouldn't sound the same as an M60, or an M40. And, I assume that if it would sound better, Axiom would've done it that way. Hope I've got that correct.

Jack

"People generally quarrel because they cannot argue." - G. K. Chesterton