I haven't modified anything engine wise on my g6 yet, but i know that quite a few other people have removed part and even all of the stock intake system which i'm sure would help with airflow, thus increasing a few MPG. If you decide to go with a CAI make sure that it has heat shields, and comes from a reputable company ie K&N, Injen, etc. Also, if you watch any of the car/truck shows specifically horsepower tv. They state that the tornado doesn't help with air flow by circulating it. it actually decreases the airflow by causing it to slow down. The whole idea of getting a new Air intake is to eliminate the bends and air pockets to create a smooth and fast flow of air.