The BMW 1 Series 135i 326hp (F20 - 2015 - 2018) produces 326bhp and 450Nm in standard form. Our Stage 1 ECU tuning file raises output to 395bhp and 530Nm, a gain of 69bhp and 80Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.