The release of the WRX Special Edition Spec R1 will satisfy those searching for a custom look from a factory car. The Spec R1 comes with MOMO designed accent pieces. 17-inch BBS wheels, and Bridgestone Potenza Pole Positions tires. The Subaru Anti-Theft System is also part of the package. Each Spec R1 will carry a unique serial number representing the limited availability of this vehicle. All WRXs are now outfitted with an illuminated ignition key ring.
So it seems to me that it is a dealer visually modified car. It doesn't say anything about performance modifications, so I am led to believe that there are none.