Darnoc.
No change to the construction of the car. Unbolt the bonnet, front wings, front bumper and rear bumper.
The rear wings are cut away a little to clear the wider set up at the rear. New front wings, bonnet and bumper. Over panels for the doors, rear wings, bumper and boot lid.
The rear wings and bumper are one unit. The front wings and bumper are one unit. Roof is as Merc built it. So no IVA required.
I don't think the headlights are E marked, but they don't have to be. When your lot in Brussels were writing the rules they said the lights must have the E mark or be of equivalent output. These are equivalent.