I have owned the X250 and currently own the XA60.5's monos and agree the XA.5's are great sounding amps.
Pass X vs XA amps sound quality in class A range
If you are one of those lucky enough and has the means to upgrade from the X (or X.5) to the XA (or XA.5) Pass labs amps, is there enough of SQ differences in low power ranges, say between 5-25W, where they all perform in class A mode, supposedly. Thanks for any insight!