One of the major problems of the synthetic race is early game population.  You barely have any, which means you can barely colonize anything.  Your population doesn't grow naturally- you have to build it which costs mineral resources and time.  It takes like 75 social production points and like 1 Durantium and 1 Promtheum to get 0.5 pop.  

So the idea is simple: when you make your custom race, combine synthetic with prolific.  The key is the prolific's +50% pop upon colonization.  The idea is to custom design a colony ship with TWO colony modules, and put 6 pop into that ship.  When it colonizes, that 6 pop turns into 9 pop thanks to prolific, meaning that you just got the equivalent of 225 social production points and 3 Durantium and 3 Prometheum worth of gains with only a single colony ship.  The key traits other than prolific are:

Movement +2 (bonus) - so your colony ships can still move around without engines.

Dense +2 (bonus)- so you can fit two colony modules on your ships.

With this strategy, you can avoid the biggest problem that synthetic races have: slow starts due to low population and no natural population growth.  

If you're a developer, please don't nerf this.  It's f-ing awesome and it's a weird exploit most people aren't going to use anyways.