DO NOT TOUCH THE MAXIMA. Keep it as nothing more than a back up daily in case of an emergency.
Like several others have said, until your financially stable, modding a car shouldnt even be a thought in your head. Hell i like to think im doing ok for myself, but things still come up that make "wants" get put on the back burner. Welcome to life.
Now when your able to get a better job and such and can at least take care of your selves and have money left over, if you reall must have something fun and reliable, like others have you before, grand prix gtp. They can be had for cheap, are supercharged from the factory and are still reliable
.