I honestly don't think that adjacency bonuses are going to work very well in X2. The reason they work so well on FiraXcom is that you only have the one base - ever. Therefore you have strong competition for space between the different room. In X2 I can build a new base, name it "FACTORY" then proceed to build all the workshops I'll ever need and reap the rewards of multiple adjacency bonuses. In fact, with X2 you might want to consider adjacency maluses so that if people want to build a factory or a lab complex they can, but the overspecialization in a base carries its own dangers.