Sorry, but that's wrong. The only time the ECU adjusts fueling over it's built in map is when it's in closed loop below 4000rpm (ish). It then tries to keep it at stoich (14.7AFR). Otherwise it has no way of adjusting because it only has a narrowband O2 sensor which is useless for anything other than telling the ECU that it's either leaner or richer than 14.7. However, the stock map may well extend beyond the "normal" airflow that you would see unmodified.
In fact, I don't think the NA even has a narrowband sensor to do that closed loop adjustment anyway. At least there's no mention of one in the tech manual.
The only real adjustment the ECU makes over it's built in map is timing, which will get retarded if it detects knock (det). However, the stock map is pretty good, so you're not going to improve it much unless you have made some big mods in which case a full remap would give you some benefits, but at big cost as has been said. And, as has also been said, the stock ECU can't be remapped.