I think Crutchfield meant that they are the only ones that are closest to OEM(6x8 plate), not that they are the only ones that fit. I remember looking through their catalog a while back, and it said the Pioneer plates were a perfect fit or something for Fords and Mazdas. You could put a 15" in your door if you REALLY wanted to.
You wouldn't need screws, just stick the magnet to the metal of the door!
