Conti has generated some confusion with the chili tires and the 4000s. The Chili tires come with the standard sidewall markings, whereas the 4000S have the silver markings and also are made with the chili compound. I can't figure out from the PBK site whether there is anything else different about the 4000S. If not, the silver markings are gonna cost ya about 5 bucks.

For the OP, I use GP4000 in NYC and have no problems whatsover. I haven't had a flat in over a year. In fact the thing about cycling since I've gotten back into it is that the tires are much better now than they used to be. Getting flats was part of the routine, but not any more. It is getting to be time to replace them and I may go for the Chili myself. I've never used PR2 so I can't say anything about those.