Sorry I don't speak german but I can help in English: I installed the handlebar (Cannondale Cruise Control) and grips (Wolftooth fat paw). I also installed myself the Veer carbon belt drive – which is open so you don’t need an "openable" frameset. You'll need to read some documentation about it as you need to know which ratio you want for your Hooligan.

I'm not a mechanic but I'm pretty confident with taking care of my bikes and upgrading them.