As far as the only possible ability for stars? No. That's just all that's built in. It looks like almost everything (not sure about strike craft) can have up to 4 abilities. Do you want your star to reduce the antimatter regen as opposed to improve it? Then write it. We have quite a few very tallented people here who are more than willing to answer your question, assist, or might even just write it in for you (afraid I'm more of the "Teach a man to fish" school of thinking).