Hi Peterayer, very impressive system! I have always wanted to audition the SME Model 30/12 with V12, but still haven't had the chance.
Seeing that you are using a full Pass Labs amplification system, and the Xono till recently, I would like to share with you some interesting experience.
Have you ever tried a Dual Xono setup, as in having 2 sets of Xonos and using only 1 channel per set? We tried that a few months ago, and got considerable improvements in every area, especially in the effortless presentation!
Now, the first thing that comes to your mind is probably double up power supplies. However, I think there is something more than that going on!
I was using a 1 module, 1 ps, Pass Lab active Xover for 2 ways Xover. Since I planned to go 3 ways, I got another module with no extra ps. While I didnt see any reason in doing so, one of my friends insisted that I tried the dual mono set up, using only half of each module (one module for hi-pass, another for low-pass), and sharing 1 single ps. To my surprise, there was considerable improvement! Actually, that was what prompted us to try the Dual Xono setup!
So, I think there has nothing to do with the ps in this case, but the 2 channels amplification stages having some interference with each other when sharing a single chassis!
If you could borrow another XP-25 from your dealer, I would be very interested to know what you think!
Here is a photo of a recent phono shootout among our group
http://i238.photobucket.com/albums/ff64/evp1312/P1040150sunset_zps6b3d6ca7.jpg