DescriptionRK Autowerks S58 CNC Ported Cylinder HeadCNC PortsCNC Combustion ChambersUpgraded Valves InstallUpgraded Springs InstallUpgraded Retainers InstallSprings, Retainers and Valves supplied by Customer or must be purchased SeparatelyCan be installed into the following vehicles:M3 | G80 | 2021 M4 | G82 G83 | 2021 X3M | F97 | 2019 X4M | F97 | 2019 Core DepositA core S58 cylinder head is required with the purchaseContact us about freight.