I'm back from my cross-country trip. Total miles on the new Avon Storm 2 Ultras is 7130. The vast majority of these miles were Interstate riding.
My overall impression of these tires is that they are a very good touring tire, and a good sport tire. I agree with previous comments that they are very neutral and slower to turn in then the Z6 front that I previously had on the bike. I would say that they make the ST13 "tossable" rather than "flickable" and require more work to turn in.
The do seem to track well with the exception that they do act squirrely for some reason on hot, dry tar snakes. I had about 4 hours of rain on the entire trip, but found them good.
They do seem to stick well and are very nice on long sweeping turns.
After 7100 miles, I measure about 3mm of tread left in the center of the front tire and 4mm on the back. The back has a bit of flattening, but nothing major. I'll post of a couple of pics.
You can see a stripe on the rear which I presume is the harder compound in the center.