[This](https://forums.teslamotors.com/forum/forums/motor-rpm-155-mp...) does suggest that the RPM of 18.000 is quie different than the 2.500 mentioned for the Siemens.

I do think the figure of 32 kg for the Tesla motor includes the fixed gear though. So I don't so why that would be of any concern.

idk I still don't understand where the unique ability of the Siemens engine is. Obviously not the power to weight ratio. Not certification as it's still in development.

As for materials and power/torque I have no clue.