Many 4x games have a robotic race, that has distinct advantages and drawbacks: No food Have to "manufacture new citizens" (this can get micro intensive) Tolerant to harsh climates (ex: better planet choice) Do you think that an ISG robotic race would do well? What would you prefer if there were unique mechanics for this race. It could also be cybernetic (think the Borg from Star Trek).
This here, could get very tricky. Everyone is on an almost equal footing. 1 ideal biome, 2 tolerable and the rest are hostile. If you have a race that gets an advantage here it could be very disruptive.
I would go into a different direction: they reproduce easily, don't need much "food", but they are uncreative and get some penalty to research.
A 100% robotic race won't need food at all. They will need more energy though. Historically the main drawback in 4X games has been to make them micro-intensive.
Hmm. If you want to custom fit them to ISG then perhaps you can make all biomes tolerable for them... but. To keep some balance, they would not have an "ideal" biome.