If you mean is it a drivetrain mule for the USDM WRX STI, then I doubt it. Since the '08s are already available here, Subaru would most likely use a WRX-bodied mule (like the white one shown in a thread posted a while back). Similar chassis or not, why go to the extra trouble of using a Legacy body at this point? Maybe it's a USDM Legacy STI mule?
As for the wheels, the distortion is probably caused by a difference in speed between the Legacy and the camera car, coupled with the wheel's rotation. Besides, if those wheels were actually like that, you'd have a serious balancing issue!