Many (many) yrs ago I used to drag race cars.
The way I remember it Forged is stronger, and more expensive. They are made by heating the steel to a pliable temperature and then stamping them into their shape.
The cast ones are made by melting the steel (or whatever) into a flowing liquid and then inserting the liguid into a mold to cool.
The cast ones should be fine if you are not reving your engine to it's limits on a regular basis.