With any reflective object, much work goes into controlling the reflections to emphasize the outline of the object or to give it a smooth appearance. This could be important if you are trying to document damage to the cars accurately. It might entail, in addition to lighting the cars, setting up large white and black cards or perhaps sheets of white paper, using carefully positioned black tape to get the outlines where you want them. If the setting is something like a repair shop where there will be many distracting objects all over the place, you might need to tent off a studio space to do this adequately.
I'm going to have to agree with Michael and recommend that you hire a professional to assess the location and your real needs in terms of image quality to do this right.