No Bombaywalla, ... the amp does not double down wattage at 4 ohms. In fact, if you checked out some reviews of the Ref 150 (not SE), you will see that the amp puts out between 150 and 165 watts if the amp is hooked up to a speaker load that matches the nominal tap value. IOW, the amp will deliver between 150 and 165 watts if it is driving a 4 ohm nominal speaker load off the 4 ohm taps; an 8 ohm nominal speaker load off the 8 ohm taps, and so forth.
It's really a function of how the amp is configured. Although its output impedance is "low'ish" for a tube amp, it does not produce power like a SS "Voltage Paradigm" amp.
I still own Paradigm S8s (v3), which are pretty decent over-performing speakers. The rated sensitivity of the S8s is 92 db, which is considerably north of the Salons. Hence, I can cleanly drive the S8s to ear splitting levels.
BombaywaIla, I get the practical electrical realities you explained above. I surmise you would respond similarly if I asked your opinion about matching up the Ref 150 to the Magnepan 3.7s, which I recall have a sensitivity in the mid-80s as well.
My bottom line is that I like my current electronic set up, ... all ARC. And I am inclined to keep the amp. Hence, I surmise that if I was interested in switching out my speakers, I would be well advised to consider speakers that have rated sonic sensitivities closer to my S8s than the Salons or Maggies, i.e., go high 80s or low 90s.
Thanks.
Bruce
P.S. -- My DEQX is off-line. Although it adds a lot and mitigates a lot of room problems, in the end, I'd rather suffer the time delays caused by the high order crossovers than the artifact effects of adding an electronic device to the signal path. I'm kinda' inclined to swap out my Ref 5 SE for the new ARC Ref 6, which is attracting rave comments. Hard to believe that the ARC electronics can be that good, but hearing will be believing.