The only dumb questions are the ones not asked. DINAN is a manufacturer/ tuner of BMW cars and CAI is Cold Air Induction. Basically stated it is a way to funnel colder air to the cars throttle body thereby adding some HP (maybe 5-7). On most of our ars the path to the throttle body is by way of plastic tubing from the front grill area, so we already have a fom of CAI. A low pass air filter MIGHT, help, but I would leave sleeping dogs lie.