Really no need for this, I was going to rebuild it, but I have gone another route with my future trackdays.
Original trans off of my MS3, had about 53k when I pulled it to do a clutch. I had a grind on downshifts from 3-2 at nearly any RPM, but nothing on 1-2 or 2-3 upshifts even at WOT.. which doesnt sound like a syncro issue. In the 53k, the fluid had been changed with MT90 twice, so Im pretty overkill on maintenance. I honestly am not sure what the issue could be.
I drained the fluid expecting to have metal shavings or flakes, but with a magnet through the gear oil I had nothing, and with straining it through a screen I had nothing either... I had a killer deal one out of a wrecked unit, so I went ahead and swapped in the lower...