While speed has \'km/h\' next to it, in the end, it\'s closer to m/s.
Also, one sector is a bit smaller than 2km³, Daedal is right, 1,3km³.
After visiting a few planets on HSZ and checking their length and width, I can state they\'ve a diameter of 481m.
This might be adjustable in the server files, though.
Other than that, it still gives a pretty good idea of scale.