When I had my Muse Studios, I ran them for a while with a Pass XA30.8. Eventually I moved "up" to a 350.8. I preferred the sound of the 350 to the 30.
Now, that may have been because of differences in voicing. I never went out of Class A with either of them on the Studios.
With the 350.8, I felt the sound was more lively, less constrained, and more transparent. YMMV.