PS2s seem to be in stock ($299 for the rears) continuosly at Tirerack. So they're out there, just not sitting in your local garage, dealership, or tire center. Of course that doesn't help much if you're on the road stranded away from home.

I had a punctured tire 600 miles from home on my first day of Crossfire ownership. The hole was fairly large so the sealant didn't work. Fortunately, I was able to call a 24 hr repair center to come out and plug the tire.

Would I travel a long distance in my Crossfire now? Yes. But I will make sure to carry a tire plug kit with me since in-tread punctures are probably the most common cause of flat tires. Replacing the empty tire sealant bottle costs much more than plugging a tire anyway.