Impact safety is probably relatively standard, as the Mondeo is produced in Europe and most safety equipment is integral into the platform and the costs to have 2 platforms would offset any cost-savings of not having those features in Mexico.
Besides, there are no US laws on how safe your car must be in order to import it into the US. The requirements are only upheld to automobiles sold within the US.
DOT Lighting Regulations might give you some hassles, as well.
More than anything insurance would be a [censored]. You couldn't insure the vehicle, only the value of the vehicle, which is an expensive proposition. On top of that you'd have to do all the work on the car yourself and pray there's no recalls, as no Ford dealer stateside will be able to work on it.
