Just looking for some information on the specific differences between difficulties?

The Wiki says it's just speed of building, amount of income, with 'Normal' having a short pause between actions.

Usually I would play on normal because I hate giving AI more cheats than they usually have, but here is an example of an undocumented difference in difficulty:

Playing as the Empire, having played the Maw story mission in both normal and hard, in Normal the mission is pathetically easy, but in hard the enemy fleet is maybe double the size with a heavy capital ship in there.

So obviously the story missions are tweaked, is there anything else not mentioned in the wiki or a more reliable source for the details?

Cheers.