I replaced my rear Michelin Pilot Super Sports earlier this week with another set. They lasted just over 10k miles of mixed use, mainly street with some autocross. A few notes:
The fresh replacement tires are much, much stickier than the ones I just took off. Huge difference in the amount of throttle the car will take while cornering. It's clear the old tires had heat-cycled out or hardened.
There was noticeable chucking on the inside of the rears from autocrossing last weekend (see photo, top of the picture). This didn't happen with the tires were fresh, but perhaps when the tires got older and harder they become more susceptible to this.
The fronts are lasting more than twice as long as the rears- there is still lots of tread depth left. I know this is largely because I drive with DSC off, and I suspect the rears don't wear very well while sliding.
Overall I'm again very impressed with the PSS when new, but I'm not impressed with how much grip it lost towards the end of life. I suspect performance was very compromised over the second half of the tires life, especially wet/ damp grip. That suggests the amount of life the rears were providing great performance was perhaps only ~6k miles, making the listed 300 tread wear rating misleading.
Unfortunately I had to replace the tires on short notice due to a cut in the tread, so I didn't get a chance to test the 30,000 mile tread wear warranty.
Sorry, thought I put this in wheel and tire, please move.