Hey thanks for the quick answers

I already had a reply written up but the smart board reminded me i now got answer_S_

So if i get this right having assets in a pk3 file would be enough to 'separate' it from the code?
As long as the gpl code doesn't strictly depend on the proprietary media/assets to function properly, there is no license violation. The way the gpl phrases it seems to be that "shared libraries and dynamically linked subprograms that the work is specifically designed to require" are bound to the code and must be gpl as well. However, the maps, textures, models, and other similar assets are not "specifically reqired" by the code, so they are seperate and not bound by the GPL.
And in the case of distributing GPL media with non GPL code what sources would i have to provide? Just sources for the GPL media in question or for the whole project?
You would just need to provide the sources for the media in question, not the whole project.
At least, that's my understanding. I am by no means an expert on the subject.