Upload & Sell: Off
Just because you *can* do something does not mean you should.
My thoughts exactly.
And personally, I couldn't care less about high ISO. No matter how "clean" high ISO has become, it will never be better than shooting ISO 100 - 800 on a tripod with cable release. If you want maximum IQ, highest dynamic range, and truly rich files for post-processing, ISO 100 is the way to go.
I rarely go above ISO 800, not even with new cameras like the 5D3 / 1DX / D800.
Oh, did I mention the tripod? Get married to your tripod and never leave home without it! On occasions when shooting handheld and light is not good enough, use your speedlite. If speedlite is not enough, use strobes.