SimAudio and the Be driver on the Focal may not be a great match. I heard the 860A V2 on Paradigm Persona 5F. While I enjoyed the sound I knew I could not listen for long periods.
For a Be driver, I would look at Class A like the KRELL Duo 175XD (or the rumored new model) or the CODA #16. The new CODA S5.5 that people are raving about is also something to consider if the speaker does not need a lot of power. I have the CODA #16 and had the KRELL. Great amps, though I wonder if the SimAudio 861 would be a better match with my slightly warm Yamaha NS5000 over the CODA #16.