Which is hotter--the car, or the model? If the model is hotter and she is the subject, shallower depth of field can work quite well, shooting from 15-30 feet with a long lens like a 135,180, or 70-200, or 300mm prime and using the car as a prop for her. In such cases, usually not that much of the car is shown.
If the car is hotter, it's common to use smaller f/stops and somewhat shorter focal lengths, to pull deep depth of field and to show off the car. You can of course, feel free t mix n' match. Pick up a few copies of car mags, to see the various ways to shoot this kinda' stuff.
Women and cars go together like cheese n crackers...they are both fantastic on their own, or paired up.