Well I already did that before even thinking to post something here..
My problem is that I don't find exact information about the used current, microstepping etc. for the axes motors or the extruder motors.
The models are:
Extruder 0: 17PM-K342BG03CN
Extruder 1: 17PM-K142BN07CN
X Motor: KV4239-T2B011 (KV4239-T2BX047)
Even though the Model name is a bit similar I'm not quite sure if these data are the right and would like to compare the settings with someone who already did the upgrade (read some posts about others but unfortunately didn't find anything useful).