As both these model-years concern the same series of Focus, there would definitely be some interchangeability. Body panels should interchange readily (provided you don't try to fit the hatchback from a five-door to the boot of a four-door) and many interior fittings would also be able to be swapped (provided the interior colour and trim materials of the two cars matched). Mechanically, however, you need to be a bit more careful. Obviously, there would be major differences between the driveline of the diesel version and the more common petrol model, but there will likely be differences to driveshafts and all sorts of components when you compare a manual Focus to an automatic one. Different trim levels can also cause interchangeability problems in terms of a base-model car not having the electrical wiring to support the convenience equipment of the upmarket version. Things like the power windows in the rear of a Focus Ghia, for instance, will cause problems in the base-model CL which relied on manual rear windows.