Head gasket = yes.
Forged Pistons = no.
Changing the internals of the motor often have side effects that most people simply do not consider. For example, changing to forged pistons often changes the combustion frequency within the motor. No big deal right? Wrong. Now your factory knock sensor doesn’t work as intended. The frequency the knock sensor is tuned for the old engine configuration and now the motor is knocking and you and the ecu have no idea it’s happening…so what was supposed to make your engine stronger (forged pistons) will actually contribute to its early death.