I wouldn't think they would need to upgrade. If you don't want them anymore, then scrap them and rebuild. Normal resource facilities don't take that long to build.
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"The difference between very sophisticated technology and magic is a very blurry line,” Dean Kamen, Wizard of IT
Researched Planetary Bombardment Missles. Got all 5 levels with one research level, and in the Ship build area it seems to only list the version #1....
Fixed in both v1.2 and v1.0
Will be updating the PBW games to v1.0d, which will also provide the extra-distictive roman numerals on the advanced drive reactors.
Anything other than a v1.0 would break the savegames.
Reactor level 5 gives you a speed 3 engine (hence the roman III for the component)
To distinguish the level 6 (which is only cheaper) from the level 5, I added the X.
So its an X-tra cheap version of the speed III engine.