I currently have T30's on front and rear (not the GT version) and will be replacing the rear after only 6400 miles. I am down to the wear bars on them. I typically get more miles out of tires than this and will be going to the PR4 GT.
The front tire only has 2400 miles on it, so it will stay a little longer as there are several thousand miles left on them. When they are done, PR4 GT will go there too.
I got the extended, extended warranty and will get the TPS swap when the tires are done. If I had not been getting that done, the stealer wanted to charge $135 for the rear alone (if I bring the bike, not just the wheel). That's amazing they want that much for it. As is, I only have to pay $22 to replace the tire now, which is reasonable, but seems like it should be less since they have to remove it for the warranty job and they are getting a tire sale as well.