The first step is to remove all of the components from the car’s body (interior trim, wiring, carpet, seats, etc.). Then the doors and all other cavities (such as the pillars) are cut open so various materials can be stuffed or welded into those voids. Depending on the level of protection desired, the doors and pillars might be bolstered with steel plates, a combination of ballistic nylon and Kevlar (similar to the material in bulletproof vests), or both. If the doors get too heavy, a third hinge is added. The fire wall and rear bulkhead can be steel-plated, too, but the floor and ceiling are generally lined with ballistic fabrics. The stock bumpers, designed to crumple and absorb energy during major impacts, can be reinforced to allow the armored car to, for example, bash through an improvised roadblock without damaging the radiator. The goal of armoring is also to make the car appear to be unmodified, inside and out. here