More power, balanced output, better power supplies... I think you'll hear all kinds of improvement with a Pure BiPolar or GS-1 Mk2 or GS-X Mk2 in bass impact, separation and layering, maybe refinements in treble and more. I tied up my loose ends with dynamic stuff with a Pure BiPolar from spritzer.
As for the GS-1 Mk2, I hope to see one at November or Can Jam NY next year.