GENEVA, Switzerland - The Porsche 911 is celebrating its 50th anniversary with the launch of the latest 911 GT3 at the 2013 Geneva auto show.In 1999 the then 911 GT3 set the benchmark for sports cars with what was the fastest production car lap of the Nürburgring-Nordschleife and established a reputation for itself as the definitive circuit-bred sports car. A total of 14 145 GT3 units have since been built the four model generations.350KW ON TAPThe engine, transmission, body and chassis are entirely new, Porsche says, to extend the breadth of ability offered by the previous 911 GT3 by an impressive margin. Its extensively modified 3.8 flat six is capable of 350kW at 8250rpm and 440Nm at 6250rpm. The engine is mated to a seven-speed double-clutch gearbox.The six-cylinder engine is based on that of the 911 Carrera S but Porsche is using active rear-wheel steering for the first time. Depending on the speed, the system steers in the opposite or the same direction as the front wheels, improving agility and stability. Among other new features are an electronic, fully variable, rear differential lock and dynamic engine mounts.Traditionally, the 911 GT3, is a two-seater based on the lightt body of the current 911 Carrera. However, the front and rear are always model-specific. For this latest generation, the 911 GT3 is 44mm wider than a 911 Carrera S across the rear axle. Another clear identifying feature is the large, fixed rear wing. The model can reach 0-100km in 3.5 seconds, accelerate to 315.3km/h and lap the Nürburgring-Nordschleife track in Germany in less than 7min30.As was the case with its predecessor, the car also has the possibility of increasing torque by 35Nm from 3000-4000rpm. It also comes with a sports exhaust system largely borrowed from the previous model.The chassis is based on that of the 911 Carrera, though lower by 30mm. Porsche Active Suspension Management variable damping system with two pre-selected specially tuned maps is standard.Check out the latest models in our Geneva show section.