Imperator: Rome Message Board  

As with typical Paradox, Imperator is mod-friendly. The values for numerous factors from tax amount to combat bonus for elephants in the jungle can easily be modified.

If anyone's interested, the hardcoded modifiers in the modifiers subfolder under common in the game directory contains bonuses for certain difficulty levels, making it easy for you to make your own modifications exclusive to you.

For example, you can get a 100% xp start bonus for every new unit in easy mode, or a 50% build time reduction or for training. Just look for the keywords under the traditions subfolder or the inventions subfolder which contain the terms needed to trigger modifiers.