Wyred4sound ST-500/SX-500 with Gallo 3.1

Looking for impressions of W4S st-500 or sx-500 with Gallo 3.1. Would it be worthwhile to go for the ST-1000/SX-1000, or is the ST-500 enough power and current to make the Gallos sing. I would be pairing this with a Peachtree Nova to use as a DAC/Pre.
I'm running my Ref 3s with 12 wpc SET monoblocks, so I imagine even the wimpy 500-watter could handle the job nicely :-)