Unfortunately, it is unlikely the result will be anything measurable other than different sound. Be sure the mod does not decrease the volume of air getting to the engine.. FYI--The Dinan cold air system has no ducting to the grill. If improved performance is the goal I would spend time/money on lower restriction exhaust.

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X5 4.6 2002 Black Sap, Black interior. 2013 X5M Melbourne Red, Bamboo interior
Dallas