Mechanical build was smooth, even on my shitty printer. Gears was fine but whole thing isn't stable enough and position on extruder and Z-axis motors should be on the top. I'm doing some heavy modification inspired by pyBot and another scara arms for better solutions.
But still I love this build, it can educate anyone with any kind of printer that robotic arms is much closer to you then you think :). Thank you very much for sharing this with everyone - @Williaty.