Minimum 8 ohms

Ask Nelson Pass.

Around 1986-7 at an audio store that sold some nice stuff Denon, Bang&Olufsen,Klipshorns,Nakamichi etc.I overheard a salesman call the PA5 and PA7 amps wimpy.I never had one and I dont know why he said that.I too always heard the designs from Pass were good into very low impedances.Just another story,doesnt mean much,YMMV,Bob

Threshold Stasis gear are good into lower impedance loads, but that's a bird of a different feather. Nelson Pass sold a concept, not Nakamichi's. A great idea, poorly implemented, doesn't necessarily make great gear.

If you want to get lots of current from a Stasis concept you should consider the SA Class A Series from Threshold.
They lowered the railvoltage with the same hardware (chassis, toroids, large cans capacitors and number of transistors).
With the Passlabs models Nelson Pass performs basically the same trick. Lots a models but all basically the same.\
The Class A models are the XA versions there and a pair of X-600 has the same hardware as the XA-160 but the XA-160 has a lowered railvoltage so it can deliver more current at lower loads.
Thresholds are definitely no match for Krells or Levinsons at loads below 4 Ohm. Audio tested the SA/1 mono-amp optical bias version and found that testing the power at 2 Ohms would blow the railfuses.
If you want to drive a Apogee scintilla or full version look elswhere