An inherent problem with your question is what else may have been modified or tweaked on your particular setup. Consider that an improperly jetted carburetor may permit an engine to run at adequate baseline levels, but not necessarily optimum performance levels. Same may be true with mixing and matching fuel injection components.
You did not indicate whether the ECU is original to the E9 or some other Bosch DJet. Next, it is unclear whether the Pressure Sender currently in place hasn't been modified or "remapped" or "adapted" to work with your setup versus the setup it was originally intended to fit. There are several sites that discuss care and feeding of the DJet and common modifications. Via trial and error there are many components that may be interchanged on the csi. Lambda sensor and/or an engine dynamometer feedback would be helpful to determine if the system is operating at optimum levels. For all we know, your setup may be operating even better than designed, but hard to tell via long distance. Only you can determine if performance and fuel economy is acceptable.
