The Porsche 911 GT2 is the last variant of the 997-series 911 to receive its mid-cycle update and in typical GT2 style the last update comes just before the current generation of Porsche’s iconic supercar reaches the end of its product cycle.

The all-new ‘991’ Porsche 911 is just over a year away so the facelifted 911 GT2, seen previously testing in prototype form, will have a very short shelf-life.

However, before the arrival of the facelifted GT2, we’ll see the all-new 2011 Porsche 911 GT2 RS, which is set to go on sale this October, following a world debut at the 2010 Moscow Auto Show on August 25.

This is the fastest and most powerful road-going sports car ever built in the history of Porsche, with power up by 90 horsepower and weight down by 154 pounds in comparison with the already extreme 911 GT2. The final numbers come in at 620 horsepower and 3,021 pounds in road trim with all fluids on board.

The car’s 3.6-liter six-cylinder boxer engine boosted by two turbochargers with variable turbine geometry exclusive to Porsche drives the rear wheels via a six-speed manual gearbox. Developed especially for the 911 GT2 RS, sports tires measuring 325/30 ZR 19 convert this massive power into equally massive performance and acceleration on the road: 0-62 mph in 3.5 seconds, 0-124 mph in just 9.8 seconds, and 0-187 mph in 28.9 seconds. Top speed is 205 mph.

Equally impressive is the performance from the car’s composite ceramic brakes. Furthermore, appropriate longitudinal and crosswise dynamics are ensured by the sporting RS set-up of the springs, PASM Porsche Adaptive Suspension Management, anti-roll bars, as well as the dynamic engine mounts and PSM Porsche Stability Management.

In its looks the new 911 GT2 RS stands out clearly from the 911 GT2 through the use of carbon-fiber components in matt-black surface finish, even wider wheels and flared wheel arches at the front, new 19 inch light-alloy wheels with central locking, as well as “GT2 RS” model designations on the doors and rear lid. The upgraded front spoiler lip and the rear spoiler lip made of carbon-fiber and are now 0.4 inches higher.

Interestingly, Porsche has already set an official Nurburgring lap time for the car, posting a 7m 18s effort. Production of the 2011 Porsche 911 GT2 RS will be limited to just 500 units worldwide.