FWIW i only have turn on pop. Nothing at turn off. The pop reduces significantly if i reduce the OEM base level on iDrive before starting the engine. There is also zero turn on pop when i start the car quick enough, i.e just before the ms-8 starts up.
Turbo Dynamics Hybrid Turbos, Wagner Intercooler, DPF Delete Pipe with Sports Cat, Ecotune custom map ~ 422bhp & 618ft.lbs