Is it such a big deal?

Don't forget that the VIN is stamped other places on the car like under the trunk weatherstrip. ( at least my 70 Dart is stamped there). So if the authorities really give a **** they can catch you if you change VIN plates. (I don't think they will, it would take a prick inspection mechanic to report it and they are out there). You could always go for it, what is the worse that could happen? I would think that you wouldn't want to sell the car then just junk it, the next guy might not be so easy going about it.