Two major categories of electronically controlled engine tuning

There are two types of engine tunes: genuine ECU and engine management.

Genuine ECU Tuning
A tune that adjusts the fuel and ignition timing according to the increase in intake air volume and muffler replacement and changes the limiter.
Several tens of horsepower gain are possible even with a naturally aspirated engine.
It is easy to power up more than 100 horsepower with a turbo car.
The working time is very short, so the cost is low.
Demonstrate stable performance as a whole.
Vehicle functions such as auto cruise and meters can be used continuously.
Since the genuine ECU is not intended for modification, there is little freedom.
Tuning requires changing data in the internal ROM or additional electronic parts.
Even if you rewrite Flash data, you cannot receive the automobile manufacturer’s warranty.

Engine Management Systems
Power-up freedom is great.
However, the original function of the vehicle can hardly be used.
It is also difficult to operate genuine meters.
The cost is high, and even if it is simple, the cost is close to $ 1000 with only hardware.
Even with DIY, if you include wiring and sensors, you need about twice as much.
High-end engine management costs more than $ 500,000 a year, including contracts for engineers.
Working time is overwhelmingly longer than running time.
This road is very difficult, but the return on success is great.
It is recommended to choose a race-only vehicle.

Conclusion
Neither can exceed the limits of the hardware.
It controls the optimum fuel injection and ignition timing for hardware changes such as mufflers, turbochargers, and cams.