Back in the early 60's Porsche began transforming itself from a class winner in the racing world to a future giant. The RS sports-racing cars and the lovely Abarth Carrera coupes were exciting indicators of things to come, but the 1963 904 Carrera GTS Prototype was the first Porsche with the ability to take overall victories. In 1964 the 904 won its class at Sebring, then stunned everyone with a first overall in the Targa Florio, defeating the big-engine GTO's and Cobras. Only three GTS prototypes were made; the car in the photo is the third. It was never seriously raced and is in superb original condition. This exceptional Porsche comes up for sale at Christie's Monterey Jet Center Auction on August 17, part of the week-long Pebble Beach classic car celebrations. It is estimated to sell for $450,000 to $550,000, probably ten times what it cost when new. More of Christie's offerings, including an Abarth Carrera, can be seen in the UK's Classic Driver Magazine site.