Try it out, just before you make the alien race, make a copy of "Stevefire.mdb" and put it in a different directory. This is the actual database for the game. Then create the race, make another copy, and then go check out just how nasty the aliens are. If they are pathetic, then you can go back to the original save before you created them and change the difficulty level (Game Details screen, middle left) If you put this to anything over 100%, the npr will be bigger, more advanced, etc than normal.
I do know that there is a time played factor built in so that npr's created later are not way behind the tech curve of the player race.
Let us know how it turns out.
Brian