Need help finding the name of old a game?

Hey all, i am just trying to find a old game and was wondering if anyone can help.
its a pc game and its human vs alien, you have to send out drillers to a pool type thing and drill for money and can be upgraded once, you can also hop out of your vehicle and into any vehicle you produce and about half way through the game you can choose to stay human or join the alien and the alien race started with S and maybe ended with a n