You know, I didn't. I had the original sensor cover corrode -- looked just like this, but worse. When I had Leica do that earlier replacement under warranty, I understood that I was getting essentially a pristine version of the sensor that had gone bad and that the inherent flaws were still there. This was a strategy to buy time, was not expensive (to me, at least) and let me keep shooting with my lenses.
I figure one of two things will come from this experiment with Kolari. Either I will shoot the camera for another five years, at which time the prices on used M11's will have come down a bit and I will have a fully functional camera to sell, or I will keep shooting it (I like the sensor well enough and have never felt like I was suffering from lack of resolution from this camera).
But leaving an expensive piece of gear hobbled was just frustrating -- ultimately a non-choice. And since the point of having those wonderful lenses is to use them, I need a platform to do that.
FWIW, there was a period in the early 2000's when my disposable income and Leica's prices were aligned reasonably well. But Leica's current pricing model (while perhaps necessary) has put new cameras like the M11 firmly beyond my reach. I don't like it, but there is not much I can do about it. So ya fix what ya got, and keep clicking. . . .