Actually, it's a well known fact that Wilsons work better on the 8 ohm tap on the ARCs. But it's easy to experiment anyway, I just did the other day, and indeed, the 4 ohm tap is significantly worse than 8 ohm!
I auditioned the REF160M yesterday . The system consisted of the VPI HR-X , Lyra Etna , Kronos w/ upgraded P.S. , Kuzma 4 point 11” , Clearaudio GF V2 , ARC REF 10 Phono & REF 10 Linestage and the 1st generation SF Aida . Cables by TOL SR , XLO , & Shunyata .
The amp is heavenly in triode mode , what presence , texture ,smoothness & immediacy. The female or male vocalist feels as if they’re in the room . W/ an efficient speaker these amps will be magic . The mids are so good that my friend & I concluded that the 160M are much better than the REF 750SE’s midrange . We tried to listen in ultra linear mode (REF 160M) & listened to side 2 of the LP Cantate Domino , it’s clear that the REF750SE is the King of the Hill as far as the amp hierarchy of ARC is concerned .
It seems even in UL mode the REF 160M driving the Aida’s cannot produce the huge soundstage (wall to wall) , the dynamic contrast & the ease of delivery that REF750SE brings at the table .
But w/ Female Vocals , small jazz bands , the REF 160M is hard to beat .