Guys, this car is so angular (and pearl white), I never thought about really shooting with it before mainly for the question in the following statement, but I am going to try now. I have two large softboxes, snoot, 3 umbrellas, 3 heads and ringflash at my disposal. As you can imagine, I don't want to put anything on the car, and polarizers may be ok for certain facets, but not the whole thing, I'll deal with that, but can't use multiples and lose 6 stops.
That totally depends on what you're after.
I watched a film crew doing commercials for Chrysler Corp. a few years back. They used mainly reflectors to spill light into the areas they wanted. To large degree, the car was simply lit by the sun, with a little fill so you could see the driver.
I've seen others use huge soft boxes to create an even sheen off a car in the studio.
Without knowing what you're after, nobody's going to be able to tell you what will work to achieve that look.
One glamour trick, then, that I think looks great for both model and auto:
Try a nice, even front light. Your softboxes would be perfect. But then from above and behind the two of them, aim some lights either using umbrellas or, directly into the girl's hair, the snoot.
The result is even light on the front and specular highlights to define the edges of what you want people to notice.
You could also pop on the ringlight, if you aren't shooting straight-on at the car to add a little pop to the model.
I'm assuming you're shooting in shadow or with the sun behind the vehicle and the girl. Doing this at dusk would be even more dramatic.
Good luck, and have fun.
Well attacked is a shot of the girl and the car, taken by my ex on Sunday. FYI the Z in the back is the model's personal car, she is a car nut!
McG I like your ideas, mobile power may be an issue so I'll drag out the Pro7-B ;)
Let's see if she is feeling adventurous enough to wear the lingerie we just bought and get in that car. http://www.myspace.com/littlemissjennifernicole