I haven't seen any measured data from any '250 or '350 series Pass amp.
However, the INT-150 was close to 200 watts @8ohms and 300 watts at 4ohms.
The XA30.5? That hit about 100 watts @8ohms and 200 watts @ 4ohms....while being firmly A/B at that power.
All distortion was 1%. I suspect these amps will also drive some weird reactive loads well, too, based simply on weight. The powersupply and heatsinking is quite generous.
Based simply on power vs listening habits, I wouldn't hesitate for 1 second to try the INT-150 with my Magnepan 1.6s which are an 'easy' load, though somewhat low in sensitivity.