And really does give a noticeable boost in accelaration. At 4500 RPM it sounds like a growling German Shepard. One thing though, Dinan says you have to install the Stage II software upgrade to use the Cold Air Intake. I've been told that without the software the car may run too lean with the additional air input. I also put on the High-Flow Throttle Body and will add the High Flow Air Meter as soon as it is approved By the California Air Resources Board.