The biggest update for the 2011 car is a newly designed aerodynamics package at the front and rear, and this is complemented with changes to the suspension setup and engine.
Clearly visible are the modifications to the front where a new front lip provides higher downforce at the front axle. The front wheels are also wider, with the rims growing from 11 to 12 inches giving additional grip and less of an understeering tendency.

2011 Porsche 911 GT3 RSR race car
The 4.0-liter six-cylinder boxer engine now delivers 455 horsepower at 7,800 rpm, five horsepower more than its predecessor. The power increase results from an engine management system that adapts even better to different fuel grades, as well as a redesigned exhaust system and modified air intake. Peak torque is 332 pounds-feet and maximum rpm remains at 9,400 rpm.
The transmission is a six-speed manual with sequential jaw-type shifting, a single-mass flywheel, hydraulic disengagement lever, a three-plate carbon-fiber clutch and a limited slip differential. The body consists mostly of steel but thanks to a series of weight saving modifications, the whole car tips the scales at just 2,689 pounds.

2011 Porsche 911 GT3 RSR race car
The 911 GT3 RSR joins the 911 GT3 R and the 911 GT3 Cup as the top model of Porsche’s motorsport product range. Pricing starts at approximately $542,000 plus taxes, and if you’re thinking yourself unfortunate for buying a 2010 model, all of the latest 2011 updates are available as a kit for cars from the 2010 season.
[Porsche]