Engine output is not changed with SW updates on the US NA engines. In some cases with European 320 diesel versions, engine output has chnaged with programming. But often not for the better (Problems with the diesel particulate filter).
In some cases trany hesitation with steps or a power curve dip on the Euro spec 2.5 Litre 325 have been helped with the latest update.
If your car is running well, donīt bother with software updates. You will not gain ANY power.
Iīve had the latest updates installed on my early June 05 built 330 (needed th updates for Daytime Running Lights), and thereīs no change in engine behaviour whatsoever. The update only messed up my Cruise control that now intermittently does not accept th 5mph increment inputs.
No, not THAT kind of tierfreund!