Free advice - I like to do these edits in at least 2 layers. I strip the vehicle from the back ground just doing a clean selection. This way my edits to the vehicle and my edits to the back drop do not get tied. Then flatten, come back and do a very and I mean very subtle blur along the vehicle to background edge so the edit isn't too defined.
Sometimes it pays off to segregate a panel as well. Like the hood or a fender so you don't have to be extra cautious in tool sets.