Welp, mine finally wore through, just in time too, tire arrived today. Noticed the first marks while at work. Stopped at a gas station about half way home, the first half is interstate.
Before leaving work, 3872 miles.
Mid way home, this is 3896 miles.
I didn't line up the picture very well, but the bottom half of the second pic is the same section of tire as in the first pic. In that section there is a significant difference in wear over those 24 miles. Also, the wear topmost wear in the second pic was not apparent when I took the first. So, when these tires go, they go very suddenly. For comparison this last pic is the same I posted earlier, that was just over 3600 miles (like 3620 or so). And there was only the tiniest bit of wear apparent, 4tune8 even said they look brand new.
So, if you're on the stock tires, inspect them frequently, don't just guess about how much you'll have left. That said, I got 3922 miles on them all told. Forgot to take another pic before I brought the rear wheel to the shop, but I asked them to save the old tire for me (figure I can throw it on for a dyno run someday, if I ever get around to it) so I can post the final pic later.