which amps is recommended with SF Guarnei Homage ?

I heard the SF Guraneri Homage with a 20W Jadis tube amp. The sound was great, but not very detailed and not very open.
a. Is this the way these SF sound with any amp., or does
it take another amp to make them sound more detailed
and more open ?
b. Which amp ?

I think SF guarniere needs power, I used with gamut d200mk3, it was better than JR concentra I, and better than ARC VT100.
Agree with Georgemg, the G's are not very efficient and like power to open up. I am using a Rowland 8 that puts out 250 watts per ch and the G's smile, detail is amongst the best I have ever heard. Apparently they also like tube power, although I have not heard them much with tubes. I did hear them with BAT 60's and they were a good match. Jadis makes great amps, but 20 watts is not enough to really drive G's IMHO.