It’s not just more power though. My car has two version 130hp and 155. For the 2 grand I got 25 more horsepower and bigger brakes ,bigger clutch , bigger wheels with wider tyres and an LSD. The only time I can recall where the engine has been exactly the same inside was the mini one and Mini Cooper where the ecu only allowed for 86% throttle on the lower powered version. Every other engine has had a mechanical difference internally to support more power.