QUOTE (0warfighter0 @ Jul 15 2008, 04:10 PM)

BUT, if you build another MCV you could have both the subfactions! That wouldn't be good would it?

I think not cause this bug.
QUOTE
The problem is, that you have to build right after GAPOWR the Powerup to get the new buildoptions. If you build something between the PowerPlant and its powerup it doesn't work anymore.
But for someone who makes a mod this shouldn't be a problem, if he has after the MCV deploy the subfaction upgrades as the only building options. So the player can't build anything else.
Before you get Another MCV you will surly build many building before that. So you can upgrade on new GACNST but you won't gain any of new tech tree.
PS.This only theory no time to test in game.