Hello everybody,
in response to my complaint about the grooves,
Shapeways has sent the following statement:
Hey Manfred,
Let's start off by saying sorry! We work hard to make sure you are 100% satisfied with your purchase. Unfortunately sometimes we mess up.
To make sure you are completely satisfied we just placed a new order for you at no charge. 
Your new order will ship by: 2021-10-25
Well then, let's wait and see the new
MotorGearboxCombo-Pair in Smoothest Fine Detail Plastic (XSFDP), I'm curious.
