The Porsche 911 GT3 RSR, the latest version of Porsche’s top customer track car, is ready for delivery for the 2012 racing season, priced from $533,000 — plus tax. The first customer cars will be shipped in January.

The biggest changes for 2012 are to the body, which grows in width by 1.9 inches and features new ducting, with intake air to the rear-mounted 4.0-liter boxer engine now fed through side scoops that replace the engine compartment top airscoop.

Engine output is restricted down to 453 horsepower. That power is harnessed through a six-speed sequential gearbox with steering-wheel-mounted shift paddles.

Porsche says the latest 911 GT3 RSR — it’s still based on the current 997-series GT3 RS street car — is built to conform to the ACO’s “LM” GTE regulations for 2012, which means it’s eligible to compete at Le Mans and in the FIA World Endurance Championship, as well as the International GT Open and other series.

With typical Teutonic understatement, Porsche Motorsport boss Hartmut Kristen noted: “Our customer teams can expect a technically mature, high-performance racecar with which they will be highly competitive at international long-distance races. Our test program on various international racetracks is currently running at full speed. We are very pleased with the car’s performance and driveability.”