Installed on my 06' 9-5. Installed fairly easily and has helped throttle response and a slight bump in fuel economy which was interesting. Can hear the turbo spool and blow-off now too. My only concern living in Michigan is how prone this will be to water and snow ingestion. Only time will tell.
Getting the old air box out is the tricky part but if you take the small screw out of the inner fender cover that connects to the bumper you will get enough flex out of the bumper to pull the air box out with the rubber hose still connected. I didn't remove the headlamp like the photos show as it seemed like more trouble than it was worth. Everything installed from the bottom with enough clearance to get a stubby in there to tighten the clamps. The other part is then removing the old air duct that runs up the middle of the radiator...Rating: [4 of 5 Stars!]