>I become aware of this while on my friend Ford Fiesta as he enabled some features which were not available even in the most expensive model.

As someone who has owned a Fiesta, and worked on a Ford auto assembly manufacturing line, I'd love to see some evidence of this. What features are you talking about? Because, having actually built seats for Ford, I know that they explicitly did not include heaters when they were not ordered. It was trivial to just not include the part; the assembly line was designed that way. You simply grabbed one cushion set vs another. Most auto manufacturers are actually concerned about margins and costs, so these things matter.

Don’t have the full list but the couple on my head were automatic wipers, and automatic rear view mirrors closing/opening.