BMW Z4 (2003-2005) MS45 ECU Tune - Stage 2See our full write up for more details and other tuning options! Stage 2: Ideal for major power adders such as forced induction. Our Stage 2 ECU tune can also benefit naturally aspirated race engines making >20% more horsepower than standard through modifications such as large duration and high lift camshafts, individual throttle bodies, and head work. Stage 2 includes the same parameter revisions as Stage 1, plus additional modifications to injector