The BMW Z4 2.2i 170hp (E85 - 2003 - 2008) produces 170bhp and 210Nm in standard form. Our Stage 1 ECU tuning file raises output to 185bhp and 235Nm, a gain of 15bhp and 25Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.