PS Station spacing is where it needs to be in each specific and unique city
and according to the overall transport plan for that city, not according to
some textbook formula. There is no such thing as a "real metro" except in
textbooks. You adapt the most relevant technology to the needs of the
130 km/h you need to raise average speed on segments longer than a few km.
You don't want to put a low upper limit on your ability to raise average
speed. If your service only has shorter segments and will not require
longer segments in the future then, yes, you can have rolling stock with a
lower maximum speed.