Setting the standard for MAF style intakes with a velocity stack, airflow straighteners and composite body for ultimate performance. Feed your SF [Intake cold air] using the Subaru factory snorkel. The SF Airbox turns your SF Intake into a [cold air intake] with OEM looks and fit.
This is what led me to believe it was a CAI. And what the heck does "SF" mean?
The sensation is as hard to forget as it is to ignore!!!
Short Flow I believe. It technically doesn't pull the air from outside the engine compartment but I think the box makes it similar to a cai because it blocks some of the engine heat.
Maybe the difference is the wrx now has more hp from the factory.