i only read halfway down the post so i might be repeating someone here, but the WRX is a low emissions vehicle. it can be done, and it can be done better too. ofcoarse, they did need 3 cats to achieve this....but in theory and turbocharged car can get just as good mileage as a n/a car. its all about tuning. if they get better computer sensors and controls in there, it wont have emissions problems.