That's generally for airflow through the radiator, to keep the temperature in check, as I understand it. Not sure how much if anything moving air into the front of the vehicle would improve power, particularly if there's a turbo in the loop anyway.
It helps stop heat soak which in turn helps keep charge temps under control and therefore air density as high as possible. I'm sure you'll not gain much power, but it'll help reduce loss after a couple of pulls - that intercooler really needs moving air for efficiency