....and some more questions.....
Hi Memez,
I am no official, just the track announcer, but I know one or two answers :

The german rules can be found -in german only- in the "Download" section of the www.d-r-o.de page.

What do you mean with "coverlet for the engine" ?
If you mean a "anti-oildown" diaper, this is mandatory in various sportsman classes, look in the rules.

In the ET classes, you may choose your index before every qualification run,
and before every elimination run.
Your index time must be displayed on the car (left side)
or displayed on a sign-board that is shown to the line-up crew right before entering the burnout zone.
There is no breakout, if you run faster than your index in quali, the run is invalid,
if you run faster in race, you are out (except when your opponent has an even bigger breakout).

The blue light indicates the "sure start" system in Super classes,
which means that both drivers have to be in "Pre-Stage" before one driver moves forward into "Stage".
Deep staging is also not allowed in Super classes with "sure start".

What do you mean if we "work with FIA" ?

Greetings from Germany,
Benni