As many Porsche 911s as you think you might see at the golf course, yacht club or shopping mall, that’s nothing compared to the legions regularly running around racing circuits worldwide. Aside from the myriad open GT grids dominated by Stuttgart machinery, the iconic German sportscar is the spec racer of choice for various national Porsche Carrera Cup championships and the Porsche Mobil1 Supercup that supports F1 races around the year. Those series use the versatile 911 GT3 Cup. With over 1,400 sold since 1998, Porsche maintains that it’s the best-selling racing car of all time, and it has just announced a new model for the 2011 season onward.
Whereas the outgoing Cup racer was based on the street-going 911 GT3, the new model starts life as the harder, faster and sharper GT3 RS. That means  … Details