Ichigo, I'm confused all over again.
As to the acrylic question, you should talk to one of their engineers regarding this on how and if it would effect performance.
Let me start from square one. LOL Making a long story short, when I first received my M22 that was missing on my order after taking a look I realized that the tweeter color was different so e-mailed Axiom and have been offered to be sent 2 new dull tweeters. My reply to them was if there was any chance I could get just one shinny since I liked it best. While waiting for the answer, the second problem has been discovered, ( Acrylic cover missing on the back of the tweeter and the wires exposed) Another e-mail to Axiom and their reply was, " We can offer you 3 new shinny tweeters and 6 woofers, would you consider this offer?". So here I am trying to decide whether to accept it or not, although this offer has been a little strange to me though, since the answer expected by me would be that they could fix the M22 with the acrylic cover missing. Did you get what I mean? Sorry for the bad explanation.