things like ...
- using a cold air intake requires a tune-up or computer adjustment
- slowing down the flow of antifreeze through the radiator for heat dissipation is better for engine cooling
- if 91 octane runs fine in your motor, a bump to 95 will make it run even better
surely the engine and car builders have learned something along the way that made them say wtf? stuff not expected and "learned" to pass along to the weekend garage mechanic
how about selecting the proper carburetor size to maximize engine performance between throttle response and peak power, oh yeah that's a good one!