I run two 600s in my system, one amp per channel. This is far superior to running one amp in stereo.
I also use Marigo Ultra 5 power cords. These are expensive (about the same price new as a used 600), but the effect on performance is astonishing. These cords are designed specifically to deal with RF issues, and this is the one failing of the Sunfire amps, so the match is quite good.
I can guarantee you that none of the commentators who disparage the Sunfire by comparison to the McIntosh has heard the Sunfire set up that way. I used to run a pair of Atma-Sphere MA-1s in my system, but the Sunfires in my system outperform them by a wide margin. (If you'd rather, I'd be happy to sell you the MA-1s instead.)
The Legacy Focus speaker works beautifully with the Sunfires set up this way. You should be able to find a pair used for $2000 or so.
I don't know what your front-end is, but for $7000 the Sunfire 600s + Marigos + Legacy speakers would provide exceptional sound quality at a bargain price.