Hi there.
It's my experience that the GR60 really shines when a lot of power is available.
I have tried a Classé cap 100 integrated but it was not a match for control, or sound.
A pair of musical fidelity xa-200 mono's sounded better, and a extra pair for bi-amping added control and performance.
I momentarily use a Roksan caspian pre, and 2 mono power blocks with very good result, but I believe that the MA GR60 will benefit from bi-amping like they did in the past.
So, I think it will sound good, but the GR60 does not reach it's full potential being a power hungry speaker and it needs a big amp to really swing.
It’s amazing how much better the GR60 sounds with high quality powerful amplification compared to an 85watt integrated.
My personal guideline: retail price of amp should not be under that of the speakers.
Good luck, and let your ears decide what’s good for you.