Are Pass Labs XA60.8 mono amps enough?

I had the Pass XA60.8's driving the Focal Sopra II and they were more than enough to make them sing with no strain at all. Pair them with a tube preamp to tame the slight brightness that Focal's are known for.

More than enough. You’re unlikely to push the amps beyond Class A. And even if you do these amps have enough headroom in A/B to tickle your eardrums.

I’m using X260.8 monos with Wilson Sabrina that are notoriously difficult to drive and I almost never see the bias meters move, which means I’m in the 35w Class A range. 
 

Good luck!

I have a pair of the XA60.8's driving Paradigm Persona 7F's, sligtly less sensitive than your FSU's. I'm very happy with the amplifiers and I'm confident they will have no issue driving your speakers.

Caution: your room is relattivly small and the XA60.8"s run very warm! I am a fan of the Tube Pre-Amp pairing, that combination will also add to a noticable increase room temperature. If you're buying new, I would reccomend purchasing from a dealer that will grant a 30 day return, just in case.

Best of luck!!

It’s not the power that is not enough. It’s just your purchasing amplifiers that are way under the quality of your speakers.

Those Focal speakers deserve better!

Try AGD amps instead or a used Burmester 911 mk3 or DartZeal