[gerrygug]

http://www.tirerack.com/tires/tires.jsp?tireMake=Pirelli&tireModel=PZero+Rosso&frontTire=05ZR70ARN3&rearTire=54ZR70ARN3&vehicleSearch=true&fromCompare1=yes

This is what Tire Rack suggests as OEM replacement. They have the Porsche N rating stamp. I have a set. They are pricey, but perform well.