Hi bflat,Cool! Thanks for the info, I won't be making those mods myself, but will check with Kitsune to see if they will offer some or all of these.
Like you I didn't dare to mod the SU-1 by myself, so I ordered from Magna Hifi (NL) its modded version of the SU-1 (the MagnaFied version), on which I ask Magna Hifi (contact Jos to get info) to replace the 24.572MHz Crystek clock by a NewClassD Neutron Star 2.
I'm currently at the beginning the the 200h required burning, but SQ is already very very nice : it's all about 3D, low crosstalk, damn nice presence, and much richer harmonics.
A bit more pricey than the stock version of the SU-1, of course, but it worths it as the SU-1 is key in my setup (see signature).
Here on the French hifi forum, I've put my 1st feedback about this device (use Google if translation is needed) : http://forum-hifi.fr/thread-974-post-156937.html#pid156937
Rgds