I have an OM603 that will be getting a Dieselmeken injection pump here very soon and am a little confused by interchangeability of injector nozzles. Looking to learn some information on the different types of injector nozzles available and which might be best applicable for a larger injection pump.

Before I did head gasket and fixed IP timing, I threw a set of injectors (Bosch India's unfortunately) at the car trying to help the idle/cold start smoking. So with the Bosch India's in the car currently that made little difference and a set of unknown condition Bosch Germany's sitting on my bench, I think it's time to try rebuilding them.

What's my best option for performance? What's the best option for cold-start/spray pattern?

I hear 3 digit numbers thrown around when referencing the nozzles (265, 314, 315, etc). What do these mean exactly?

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{2010 Mazda 3 266,000mi} - daily since new, Airlift suspension + some chunky sway-bars: fastest pass 17.7@77MPH
{1987 300SDL 256,000mi} - stock turbo @ 22lbs straight piped + a whole bunch of pre-turbo water/meth injection, 722.3 with increased line pressure, special sauce, and shift kit: fastest pass 16.5@82
{1992 964 Carrera 4 Frankenstein ??,???mi} - 993 forward dated, Speedster conversion, GT45 + E85: fastest pass 12.5@113