(http://media.il.edmunds-media.com/porsche/911/2012/ns/2012_porsche_911_actf34_ns_42711_196.jpg) The 2012 Porsche 911 GT3 RS 4.0 is the final hurrah for the 997 generation of the Porsche 911. It'll be the fastest GT3-badged 911 of all time.
The 911 RS 4.0 features a 493-horsepower, 4.0-liter flat-6. This is as close as Porsche will get to building a road-going version of the 911 GT3 RSR. Porsche will build 600 examples of the 911 GT3 RS 4.0; perhaps one-third will reach the U.S.
Source: Insideline.