I'd wonder what others will think of your M3(s) being in a small "box" like that.
I'm sort of in a similar situation. I currently have a VP150 that I feel is missing "something" so I've been thinking about getting a M22 or dual M2's to somehow construct a center out of them. My VP150 is sitting in a custom TV stand I had made (this is a pic of it in my previous home):
I tried to make it open and not boxed in as best I could. So I'm not sure if that is my issue or just the performance of the speaker. Now if I went with bookshelfs they would pretty much have to sit on the floor in front of the TV/stand. Basically would make them the same distance away from the back wall as the left/right speakers would be. But I'm just wondering if they would be too low to the ground, and also what it would look like. This will all be in my new HT that I'm still constructing.
