CSF Racing Front Mount Heat Exchanger w/ Rock GuardBMW F8X M3 M4 Front Mount Heat Exchanger w rock guard Silver The S55 power BMW F8X suffers heavily from heat soak. While the ideal solution is pairing the Front Mount Heat Exchanger with the Charge Air Cooler, you can still see significant improvements with just the Heat Exchanger. The ability for the system to remove as much heat as possible is the bigger of the two weak points in the system. So if you are planning to upgrade your S55 cooling system