Fuel Injector Manufacturing

I have some questions regarding high flow fuel injectors and how they are made. There are obviously many different companies on the market at a wide range of price and quality. I would like to know how they are made. I know that most injectors start out as Bosch or Denso “Cores” and then they are modified to achieve a certain flow rate, and I know that most companies provide flow and latency data as well as flow matching. However I’d really like to know what is involved in the production aspect, and what exactly is modified to produce a high quality / high flow injector.

Are the internal wire coils swapped out or modified?

Is the pintle valve modified?

I’m assuming the outlet section is enlarged?

Thank you!