The Siemens EMS2000 and the EMS 5150 are ancient by now, but there still is not very much information about, at least not what I can find.
Working with the edc15,16 ME7, MED17 was quite easy as there is so muh information out there along with good FR that gives you some background on how things tie together.

I'm really missing some key information about the ems2000 and how it is actually structured/working. I have a lot of maps identified, but with no FR getting the understanding on how they act together is quite a bit more difficult.
One example - axis are stored away from the maps, how to identify what axis the various maps use? How to know if it uses an 8bit version or rpm, or a 16bit version? (let's just say there are a 16x1 8bit rpm axis and a 16x1 16bit scale, also for rpm)

Comparing. JCW file to a non-JCW can reveal the changes made to give more power, run bigger injectors - but I'm missing the understanding of the ecu as it is somewhat different to Bosch. :/

Any tips on how to get a better understanding of it? (maybe I have to use Ida/Ghidra to fully understand it?)

Cool, I'll try to find the FR for MS42.

The ecu I'm trying to wrap my head around is for an old Cooper S, ori attached. (HW: S118012003B, SW: S118098706C)

Ultimately - understand it. And then optimize it. Bytetronic has a lot of wrong maps, factors and names - or so am I told.