The easiest way to edit the maintenance of you race would proably be to create a new Culture. You can find the culture settings in your space empires date folder, asumming you installed it in the dafault place it will be:
C:\Program files\Shrapnel games\Malfador Machinations\Space EmpiresIV \Data\cultures.txt
And No, I will not type that again if you missed it the first time
Just double click on it (cultures.txt) and take a look at the diffrent cultures. Negative numbers are penaltys for your race, positive numbers are advantages.
The best way to creat a new culture is to copy and paste an original one, then edit the details you want. Just remeber two things:
1.Make sure the spacing in your culture is the same as in the orginals. i.e colons in the same places, number values in the same places etc...The game is really specific about this.
2. The only exception to rule 1 is the description of your culture. This can be as long as you want, I think
Then next time you play, create a new race. And pick your new culture from the list. That's it!
If you still have trouble, let me know. I can just create one for you. It's less work than typing this message was