I say, give the M40s at least two weeks of serious listening before you decide to send them back. I haven't heard the M40s but I have the M22s and I can say without reservation that they are some of the most "detailed" (not laid back) speakers I've ever heard at any price.
When I first heard them, the detail was shocking compared to the polite KEFs I had been acustomed to. My first thought was "man, these are bright" and I keep waiting for the ear fatigue to set in but it never did. After two weeks of the M22s, I didn't want to go back to the KEFs (at least not for critical 2 ch. listening).
