Take it off IMO! We should not have to deal with a whistle from a factory product when they made great strides to improve the sound in the interior. Ford should do some R & D on their accessories before they send it out to the customers. Perfect example is the mud flaps for my truck. I have a King Ranch with the molded running boards. The mud flaps that were listed for my truck don't fit properly in the front due to the boards. A heat gun was needed to tweak the flaps but this should not be required. Like I said this is just my opinion!