THUNDERMAX EFI SYSTEM. PN#309-605. APPLICATIONS; M8 models 2023.5UP Touring® Models with center cooled motor with or without VVT. EXHAUST NOTE; 18MM LAMBDA SONDE. Installing a ThunderMax EFI may be in violation with local or EU laws. The ThunderMax EFI may not comply to local or EU emissions regulations. Check this or install at your own risk. | 