as in the bump strips and bumper lips? or the interior dash? i think your meaning the exterior.
ideally you should take the bumpers and strips of the car and mask and spray. but its possible to leave on the car and mask the rest of the car off entirely. rub down with fine grade sand paper or wet n dry. few layers of grey plastic primer, then more wet n dry if really needed. few layers of spray paint and then a layer of laquer to protect the paint. leave at least overnight to dry i would say.