S55 Stage 1 E-Flash Performance ECU Software ESS S55 Stage 1 E-Flash Performance ECU Software 550+ HP / 560+ lb-ft tq The E-Flash S55 software is a full OBD2 solution that does not require sending in the ECU or opening the ECU in any way. Take your already high performance F8x M3 / M4 to the next... MSRP: Now: €953.81 Choose Options Compare Selected