What if any would be the drawbacks of doing such? My car is no longer required to pass any emissions test, so no problems there. I'm just wondering if it is worth it. A trusted mechanic has told me he thinks I would be better off leaving the two front CATS and removing the third CAT and the resonator. My main objective is to help remove the drone at certain RPM. He told me I would have a racier tone with a higher note than the bass I currently have with Flowmaster 40s, which I intend to keep on the car.