I just dont see how the printer will work if it's threaded. As the Z-axis motors turn it will try either pull the threaded top mount towards the motor or push it away because the motor itself is mounted to the frame as well. I'm just thinking logically, and I dont see how it will work if its threaded. Too make logical sense to me, I see that it must be smooth.

It's just my logic of thinking. Maybe someone else will reply soon who has that printer and can provide more for a clear answer.