Years ago manufacturers would build a series of engines that were all the same except for the features that varied the power output. So different intakes or exhausts. Cams or turbos. It is not like that today.
The VW group make millions of engines and they do not make them any stronger than they need to be. Why spend the money on forged rods for an engine which will be just fine with cast ones? And not just the engine but the whole transmission etc is like that. Every bit of the car is costed to deliver the performance required for the least amount of money for an acceptable length of time. A simple example is the plastic coolant manifold on the front of the EA888 engines which fails and is expensive to replace. Why plastic? Because it’s cheap. Why haven’t they fixed the
problem? Because enough of the failures happen outside of warranty that it’s cheaper not to and they’ve learned from experience that people will buy the cars anyway. An EA888 that produces 200hp and one that produces 300hp are not the same engine. You’d probably be shocked to learn just how different they are.
I’ve had this conversation with several tuners and looked into engine specs and they all point to the same thing. If you up the power on a modern engine, you’re going to start breaking stuff.
Incidentally, I've had a 300hp Cupra and a 150hp FR and in all honesty, I prefer the FR. Yes, the Cupra is a damn fast car in a straight line but the FR is more fun more of the time.