I too, fell in love with the Audio Physic Virgo after owning the Step and Tempo. Without being far off from the topic, I do think Virgo II deserve a high power amp with great damping factor for the sake of the 4 woofers they have. They don't post erratic impedance so you don't need a 'double wattage--half impendence' amp. However, they do need some power there to control the woofers completely.
I agree with some of the audiophile think they tend to be a bit bright in absolute sense, and they are revealing the characteristic of your amp, pre amp, and CD player, including your interconnect or speaker cables.
I have tried quite a few amps(Krell, Levinson, CJ, DK Design, Chinese tube amp Ming Da) and different front end (Wadia, Sony, Meridian, Levinson) with Virgo II and they simply show what you have changed at the front, for better or worse. You can tell some amp/CD player/pre amp sound more musical involving, more truth of timbre per Sam Telling, throw a bigger or more precise imaging and soundstage.
However, I keep coming back to the old Levinson 23.5 which I think is the best match for them probably because of the amp rather dark sounding nature, and it seems it soothes the Virgo II, good tube amp is probably another ticket but it will be hard for a tube amp to beat the bass finesse of the Levinson 23.5. I also tried the earlier Krell KSA50 MK II and even the nuclear reactor like KMA100 MK II (rated at 0.1 ohms at over 2000 Watts, PURE CLASS A!, designed the drive the earlier Apogee full range or Apogee Scintilla) but in a way they don't match the Virgo II as good as the ML.
Regardless, the Virgo II is a very unique speakers and just like the reviews, it can literally disappear with the right placement. It requires patience and hard work to set them up properly. But once you get them sing, man, you are in heaven!
One devious thing about them is they tempt you to change your gears constantly and you can't help to wonder how the new gear will sound in the setup. And boy, not all amp
pre amp/CD player sound the same!
Bravo Joachim Gerhard!