CSF BMW F8X M3/M4 Front Mount Heat Exchanger w/ Rock Guard - SilverSignificantly reduce Intake Air Temperatures (IAT) for Maximum Performance (with Faster Heat Soak Recovery) on your F8X M3 M4 with a CSF Heat Exchangers. 2 row 42mm Core (Dual Core) Featuring CSF's Exclusive B tube Technology Core Features an Ultra Efficient Fin with 6. 5mm Fin Height and Multi Louvered Design for Maximum Surface Area Contact Dual Pass Flow Structure Allows the Coolant to Flow Across the Core of the Radiator Two Times Before Exiting