[glamprecht]

Yes you're correct - we can not confirm anything.

I have some experience with some control units in cars of which one is in the E90 and others in Audi and so on, but I've also seen some strange stuff - so we will only know how it works when we know.

As far as the ID's are concerned: you are right as well there are some control units that have ID's assigned to them. There are also as you mention ID-groups assigned to devices.

Going through some of the E90 docs I notice a mix of both approaches. The messaging is described as "data is put on the bus and ID describes the type of data". This means the data format is consistent with the ID. However when functionality is described it says Unit1->(msg a)->Unit 3->(msg b)->Unit 4->(msg c)->Unit1

We'll in summary I'm also guessing :-)

I'll be getting some more info in 2wks time, perhaps that helps.