That would depend a lot on the rubber you're using but my '08 Coupe with PS2s feels better overall at 30/31. Viper techie at selling dealer suggested 30 for the street, from experience; I've tried 29, 30 and 31 and for everyday tooling around (short runs) 30 is a noticeable improvement over the factory recommendation - better traction and handling. In my experience, 31 on highway (longer trips) is comfortable and also a good pressure for track use.
Can't comment on wear: I have 6,500 miles on mine (80% highway) and the rears seem almost new, but I don't beat the car that much from a dead stop.
