Karmapolice,
I echo you inquiry! I have noticed far more Xa160.8 listed rather than the X260.8. Even historic sales/listings of X260.8 are extremely rare. I am in the market and considering both of these amps in addition to one of the Luxman integrateds.
From my research, the X260.8 is stellar and a step above the venerable X250.8. I do not have a local dealer so an audition would be quite a challenge for me.