Harbeth SHL5 vs SHL5 PLUS

I'm not sure I agree that the larger models won't work in a small room. Harbeths are designed for control-room conditions and they can be very small. However, it is a crapshoot as to which speaker will work the best in your particular room. I think it's just an unfortunate fact of life that, in a normal domestic environment, you don't know what's going to work until you try it. Also, IMO, the HL5s sound bigger and are more forgiving of lesser electronics than the M30s. They are a great speaker in any incarnation.

That's funny. Canopus drum company claims there is a difference in the sound of the drum when wrapped with different color plastic sparkle finishes. Let me say this - I've learned not to assume someone cannot hear something just because I can't. But there are limits to everything.