Why are 318's low HP and torque?

Forged are lot stronger good for high RPM, HP and Power Assisted engine but are heavier and greater piston to wall clearance. Cast are alot more fragile but are cheaper lighter and can run tighter clearances but are mostly in low compression. Hypereutectic piston are light, can run tight clearances, come in higher compression, inbetween the cost of forged/cast, can handle more power and RPM's than cast but not as much as forged.