The BMW Z4 3.0i 231hp (E85 - 2003 - 2008) produces 231bhp and 300Nm in standard form. Our Stage 1 ECU tuning file raises output to 246bhp and 320Nm, a gain of 15bhp and 20Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.