I think if you do a lot of mods to the engine, then you'll require different (better?) spark plugs. But the reason is not because the original (OEM) ones are 'bad'; and more so because they can't handle the required load of work since they were not originally design for that type of application. Most guys that get forced induction (turbo) upgrade their spark-plugs as part of the kit. Also some NA engine mods will benefit from spark plug upgrades.
Other than that the old adage stands true; if it ain't broke don't fix it
