Which Amplifier for Sonus Faber Olympica 3 Speaker

I can't find impedance/ phase graphs on yours but:
Typically the Sonus Fabers I've seen the impedance and phase graphs of have been very difficult in the bottom end to drive, even though they are efficient.
They have needed amps that can do good current delivery, that is almost double their watts each halving of impedance from 8ohms to 4ohms to 2ohms 100w 200w 400w you get the idea.
Here linked are just 2 Sonus Fabers read the first few parragraphs and look at the first graph.

http://www.stereophile.com/content/sonus-faber-cremona-loudspeaker-measurements

http://www.stereophile.com/content/sonus-faber-amati-futura-loudspeaker-measurements

Quickly looking at the two amps you mentioned neither are going to do your speakers justice, the Hegel 300 is probably the better proposition, as it has bi-polar output devices which will try to do the doubling trick.
But even it looks a little light on if your Sonus Fabers are anything like the others to drive.

Cheers George

George - the older SF were, as you say, notoriously hard to drive due to impedence and phase angle issues. However, the newer designs are typically much less taxing. The Futura graphs look more like the old designs, which may simply mean that they kept some of the old design. Stereophile did review the Venere 2.5 and found it much easier to drive than older, higher end models. That is not surprising since it is meant to be a more entry level offering. I believe part of the design criteria for the Cremona M was to make it easier to drive than the original Cremona. I believe they probably carried over that philosophy to the Olympica design. Since Stereophile has not measured the Olympica 3 it is hard to know how easy or hard it is to drive. But my guess is that it will much easier to drive than the Cremona or Amati Futura that you reference.

Venere 2.5 Measurements

My local SF dealer demos the speakers with both Audio Research (reference series) and Rowland SS amps with excellent results.