Are Pass Labs XA60.8 mono amps enough?

The references above to the X260's is somewhat misleading as the X amps are a Class AB design but biased into Class A at low powers, as opposed to the XA amps which are Class A designs. However, it is worth noting that the maximum power output of the XA 60.8s is well above their nominal rating. John Atkinson measured 150w into 8 ohms, 240w into 4 ohms and 380w into 2 ohms. From personal experience, they will not feel short of power in a small room.

Pass labs uses mid grade capacitors and decent parts but very old old old old circuit designs where they focus the most on the first watt. They won’t give you the dynamics of more sophisticated circuit designs.
They won’t have as much grip with lower depending factor than Burmester.
They won’t sound as musical as AGD and won’t have the air on top of soulution or DartZeal. The 50 watt class a Gryphon Essence would be perfect as well. It is class A and doesn’t run out of gas as the pass labs will. It also will sound more accurate with better tone, texture, dynamics and air with more microdynamics and less color of pass labs house sound.

Think of pass labs as a 1980’s Mercedes S class and the more modern amps like BMW M4 Competition Xdrive coupes. 
you don’t need a Ferrari or hyper car to get 95% out of your speakers but that old Benz will be surPass labs and will be less than capable.

Agree with your analogy but most in this hobby and especially at your level look to get another 1% maybe 2% and if lucky 3-4% improvement out of their next upgrade. You asked the question and have choices.

BMW M4Competition Xdrive= Heavy, Complicated, and Ugly.