Some questions for the german boxed Version

There is a german boxed Version for the game. These translation is only available with this version, not via stream. I have some questions, maybe you can help me.

* This is the normal steamversion just with a german translation, right?

* The german translation is not perfect, will there be translation-fixes?

* If you activate the german version via stream, can you switch to english if you want?

* Can I use further patches and DLCs with this version, without getting it back to english?

* Are the DLC-translations with it, if you buy these later via stream?

* Do some of you german guys have experiances with this boxed version?