S54 ITB Adapter Kit for M50/S50/M52/S52US EnginesWith the RRD S54 ITB to M50 M52 S50 S52 Adapter Kit, you can now properly add the S54 ITB and Airbox induction system to your M50 M52 S50 S52 based engine. We have given you the option to buy the adapter kit if you already own a set of S54 Individual Throttle Bodies. If you need a used S54 ITB set, we have limited stock. The full adapter kit comes with: RRD CNC Aluminum cylinder head to S54 ITB adapter plate Hardware (Screws, washers, o rings)