Alright... I did my tests. Some of them worked out well, some of the not.
But I am really ashamed of myself...
When I unpacked my printer, it seems that I was so excited, that I messed up the ABS and the PLA rolls. Ever since I thought I was printing ABS, but acutally printed PLA @ 255°C.
This explains a lot.
Currently I am testing the printing with ABS at the right temperature and I am overwhelmed by the quality I am getting. It's like I got a compleatly new and better printer. Hahaha
Lessons learned: Always check fillament twice.
Thanks anyway for the kind support.
I might eve