With modifications the ECM's (electronic contol module) need to be recalibrated to deliver the proper air/fuel (A/F) ratio to meet the modifications so the car doesnt run lean. ALSO modifications to camshafts like performance cams OR to the rocker arms such as higher ratio rockers require a ECM recalibrations for ignition timing advance curves as well... more so for performance cams than rocker arms.
Now with a stock engine such as yours it can be driven hard and/or easy and the computer (ECM) just delivers the proper fuel ratio and timing advance accordingly to the information it recieves back from the various engine sensors.
A quick and probably not so complete basic run down of various functions:
You have a throttle position sensor (TPS) that tells the computer how much fuel delivery you are asking for. It adjusts the A/F ratio (and timing) accordingly
Then there is the O2 sensors that tell the ECM what the A/F ratio is and it adjusts accordingly.
Then you have a... forget the proper term... air intake temp (I think AIT) sensor that tells the ECM air temp which determines air density and ECM adjusts accordingly.
Then you have a MAF (mass air flow) sensor that tells the computer how much air is being fed into the mix (in conjuction with the TPS) so it can adjust the fuel thats injected from the injectors to keep proper A/F ratio.
Then there is a knock sensor that tells the ECM if the timing is too advanced causing preignition of the A/F ratio and adjusts the ignition timing accordingly.
You have a crank position sensor that controls the overall ignition timing
You have a cam sensor that controls the overall fuel injection timing
All these ratios and timings are precalibrated into the ECM for the proper stock performance of the engine and it just does the rest according to what the sensors tell the ECM is going on.
Alot of what you are being told is "folklore" that more applied to much earlier more primitive systems, such as less refined throttle body injection systems... and primarily had an effect on engine start up and cold idle.
If you car is running good with no check engine lights... its a happy camper, always delivering the proper A/F ratio and ignition and injection timing. If it throws a check engine light have a tech diagnose the problem and replace the proper sensors or parts if need be and it will continue to be a happy camper.
