The Ayre wood blocks , under the KGSS are, in my opinion, a mixed bag. Less sizzle on top but more recessed.
The Ayre wood blocks work wonders under the Ayre gear (no surprise) and are less predictable under ofther stuff.
The problem is/was that a lot of other stuff happened, since the last time the guys were here.
New power cord on the integratred and KGSS.
Different power conditioner. Different power cords from the wall to the power conditioner and the racks were finally filled with sand.
No telling what the cumulative effect of all this was.
BTW, I had an extended audition with the O2's before I purchased my own pair, while at the same time having the SR 404's.
The SR 404's were MUCH better with the KGSS than the 717, but so were the O2's and the SR-404's 2-4k peak, which bothered my ears, did not go away.
I hope this helps the person who is wondering about the value of the KGSS.
Jay