Ad absurdum.3.15 With the exception of the parts necessary for the adjustment described in Article 3.18, any car system, device or procedure which uses, or is suspected of using, driver movement as a means of altering the aerodynamic characteristics of the car is prohibited.
If a driver moves his right feet, changing throttle position, exhaust gases flow changes as well.
If this car uses it's exhaust to influence aerodynamics (AFAIK all 2011 cars do, maybe except HRT), than this car is illegal.