A protective screen for the oil cooler on the S63-powered F90 M5, including the M5 Competition and M5 CS. The F90 carries its coolers low and wide behind the front bumper, where they take the full force of anything thrown up off the road.
The M5 is a heavy car that makes a lot of power and a lot of heat, and it is used for long, fast highway runs — which is where stone strikes are most likely. The guard keeps gravel out of the fins without choking the airflow the cooler depends on.
No tune is required, nothing emissions-related is touched, and it ships everywhere including California. Worth noting: the F90 uses the S63 and the G90 that replaced it uses the S68. Parts do not carry over between them.