I kept my old SC board. The reason I did is I have a theory that in my case the thermal paste on it was inadequate. The replacement, perhaps refurbished by the ebay seller, had probably too much thermal paste on it, but it's still working peachy keen. So, should the replacement SC board ever fail, I may redo the paste on the original one and see if it behaves better than it used to.
Can't recall if I set the vsus back to its default value or not after changing it to see if it would help with the original board. (Just made reminder note to check...) At the time, changing it made no difference, got purple haze either way.
But anyway, cool that you got it all fixed up.