I am interested too Gunbei.
I found the AU24 more forward and detailed than Mat Ref MKII in my system. It has a real see into, holographic type quality. Along with the before mentioned bass differences. As with the Hologram speaker wire I found the Mat Ref to have a nice golden quality in the mids. I never owned the Silver Reference MKII but my friend did and he found it compared with the AU24 in overall detail and tone, slightly preferring the AU24 in the end, which as we all know, could go either way with yours or anyone elses system.
BTW David D,
In the AZ line, I ended up thinking that the best deal was a Mat Ref MKI IC that offered much of the performance of the MKII at WOW type prices, which are usually about $150, with quite a step up from the WOW, much closer to the performance of the Mat Ref MKII. Ask if the Mat Ref MKI looks similar to the MKII, if it does it is the latest version of the MKI and better yet. The older Mat Ref had quite a different look without the same locking WBT RCA ends.
I hope this helps...