The NEW ProTune II 4.0 software is compatible with 64-bit and 32-bit operating systems (Windows® 7 and later). It offers two levels for tuning your S&S VFI (Variable Fuel Injection) ECM (Engine Control Module), basic level for general tuning and advanced level for detailed tuning. The requirements of a specific tuning job and the tuner's level of skill should determine which level is used.