The Citroen C4 2.0i 16v 138hp (2004 - 2010) produces 138bhp and 190Nm in standard form. Our Stage 1 ECU tuning file raises output to 148bhp and 210Nm, a gain of 10bhp and 20Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.