I have listened to the Audience AU24 IC in my system for 3 days now and can say they have quite a bit more detail and nuance than AZ Mat Ref MKII. Also the tonal balance is much more to my liking and seems to favor no particular region where the AZ favored the bass and the high end always seemed recessed. I am not sure if this is a function of soundstage or frequency response (or both), even though I agree the Au24 is more forward I just prefer the perspective it offers. Also on the AU24 I prefer the way the bass integrates with the rest of the sound, gone is the constant bass 'drone' or 'bump' and replaced with articulate bass, the word plumey keeps coming to mind, the bass has pluck, if these words make sense. I guess the bass is more articulate and nuanced and can be quite powerful if the music calls for it. Bottom line is the AU24 is neutral, detailed and refined and the AZ is smooth, tuneful and warm.
In my stereo it is no contest as I think my Reynaud Trentes and the Plinius 8200 MKII are both slightly warm and benefit from the neutral and detailed quality of the AU24. I will not bother with the Silver Ref as I am pretty darn happy at this point and a friend who replaced his Silver Ref MKII with the AU24 confirmed that the AZ has more bass drive, something my stereo does not need.
thanks guys
Happy Holidays
Phil