I have a 210mm diff here, too. I considered the Quaife for that one, and we may still go that route for @QuadPrism's SRT-6, but pretty pricey option. Quaife is a good differential, but not as good as Wavetrac. Their 210mm diff is for a W124, and while it fits the ring gear in a 210, it does not fit the later housing.