Integrated Amplifier for Sonus Faber Guarneri Evolution

A wonderful integrated and better then pass labs or McIntosh ,hand built is Aacphase from Japan , either their E380 or even better sound their new E4000

At our audio get together I heard them all on the same weekend their attention to detail is superb unless you have $23k for theNew Gryphon Diablo 

which. Is the best but very costly . My friend bought the Accuphase E4000

the refinement and realism is fantastic , Perrotta consulting , is my go to for upper end like Accuphase .

My feeling is when it comes to these things, you'll never know a good match until you try it. Some great amps have been mentioned here but I'd add one to the list: https://www.audiogon.com/listings/lisb62ag-modwright-kwh-225i-stereo-tube-hybrid-integrated-amp-52620-tube.

For your money, this will likely be hard to beat and it's being sold from the music room so if you don't like it you can return it. This unit will have a beautiful balance of tube pre stage and solid state amplification. I have an LS100 pre and it bested everything else I've had in my system, including ARC, and not by a little. 

For what it's worth, I think this is a much better match than a Macintosh. My experience is that Macs match really well with B&W or another somewhat bright speaker; the pairing works out as the smooth Mac cools off the slightly glary highs. Sonus Faber don't have those elevated highs, their much more balanced and the Mac might make them sound mushy. 

Audition the Boulder 866 and you will be glad you did. Very neutral with plenty of power for your speakers. Good luck ! 

Have heard the Vitus very dynamic aND great sounding. Have heard a LOT of MAC gear over the years and it has NEVER impressed me, lack of dynamics and no body.

+1 @mattmiller McIntosh is made for Sonus!