The ballast should come with it's own wiring for the bulbs. Also, you will need a ballast no matter where you are. You may be thinking of the auto-levelling system that isn't required in some places. Ballasts are required for ALL HID lights, they will not function without them.
Your best bet is to just get a conversion kit, most are fairly easy to setup, just a few wires and you're set. I'm not sure on the malibu's, but on the Grand Am (similar layout) the negative is the trigger for the headlights instead of the positive. Make sure you work around that or your lights will never turn off.
Good luck with the project.