[TripleBlack]

Hi,
Seeing as no one was able to answer my previous questions in another post:
http://www.e90post.com/forums/showthread.php?t=746344

I was hoping that I could make it simpler and just ask; What are the separate ways of updating the 'software' in our cars?

I.e. I understand we can update the navigation software on its own.
And that an update can be done to affect wastegate rattle. Does that one come under ECU update or is that just coding the same software to do something differently?
Is there an iDrive software update? To change things like the look and some of its functions or performance?

The whole reason behind this question is that I want to attempt to make my 57 plate 335i as up to date as I can before I start tweaking it.