I agree with CatBrat on two points; it's very difficult to fully account for enclosure size, and you should CALL and ask the folks at Axiom. The inwall M22's look like a slightly bigger enclosure to me, which might help the bass extension somewhat.

Ultimately, aesthetics is also an issue. Personally, I kind of like the stealth of the inwalls, but I can see how someone would prefer the furniture-like presentation of the IW/OW.

bibere usque ad hilaritatem