That's not a highly fuel efficient model so my bet is the fuel impact is that of a second passenger or less.
As the stress, it's not like you are installing 100 Kg bumpers so if you can lift them with say one hand, you are needlessly worrying.
As to legality, you ask a lawyer. In some countries they are sticklers about everything, and in others, no one cares.
I am thinking of replacing them with steel bumpers. For this I am looking for guidance from experts. My initial queries are:
Are steel bumpers legal (refer ban on bull bars)
Will steel bumpers hinder the operation of Air Bags in an unforeseen scenario of frontal crash. To best of my knowledge the Crash or Air Bag Sensors are located in the bumpers (not sure how technically correct this information is)
Would the steel bumpers put any additional stress on the chasis/body thus causing long term damage
Tentatively, how much weight would be added to the Scorpio
Any effect on fuel efficiency due to additional weight
Shape: I would prefer the shape to be as close to the stock ones
Any recommendation for car modifier in Delhi NCR region.
Tentative cost of the project