Cool still you might gain 5HP and get a lot of droneThe only time I've read that exhaust back-pressure can add power is in one of these scenarios:
- If the factory tune can't compensate for the additional airflow, and the motor runs lean.
- 2-stroke engines, to prevent the intake charge from blowing right out the exhaust
- If the (4-stroke) engine has a too high overlap camshaft, and the back-pressure effectively lessens the overlap. This is not the scenario for the 3.6, since it has VVT.