Based in some of the lore and abilities of the races, they should have some advantage in certain areas, but difficulty in others. Advantages like a "discount" on the amount of Research needed to unlock a tier in a certain Research Tree, or even pre-unlocked tiers. As for the downsides, maybe an increase on the amount of Research needed to unlock the tier.

The Floran for example, they are excelent in hunting. Because of that, maybe they should have the Bone weapons/armor tier pre-unlocked, and a small discount to other tiers in the "Weapons and Armor" Research tree, but disadvantage in "advanced" Research trees, like Engineering.

Sorry for any spelling mistakes, my english is bad