Dan D’Agostino and ARC Ref. 10

In solid state Bryston 28B monoblocks or McIntosh 601 or 1201 monoblocks are the best I've heard.  Never been a big fan of Krell / Dan's work. 
But if your already on-tubes, I go with either Audio Research Ref 250SE's or if you well off enough a pair of VAC 200iQ's or ultimately VAC Statement 450iQ monoblocks  
As with any upgrade thou, your mileage (improvement) will vary....

Should be no impedance match problems.
As the AGO is 100kohm input and the AR is is quite low (for a tube) output impedance

Cheers George 

I had a Dag Momentum with ARC Ref 40 in house to experiment with my Wilson Sashas. Absolutely wonderful in all respects. This combo is the perfect marriage of tube and ss for those who do not belong in either camp. I am sure they would work just as well for Evolution Acoustics MM3s which are fabulous speakers.