If you research Xeno Ethics early, there is no need at all to research Soil Enhancement and subsequent techs. An exception could be if you wanted to get the trade good Aphrodisiac obtainable by researching Habitat Improvement. * I'm not sure when this changed, but in my Dark Avatar games (DA v1.5), you still need the appropriate tech for the instant upgrades to happen. * The next major advantage of choosing Neutral are the Neutrality Learning Center. See Neutrality Learning Centers strategies