Concur w/Pat. Cast pistons good for about +/-350. Keith Black Hypereutectic Pistons start at about $200 a set and are a better choice with forged pistons being the best, but at over double the cost.

That said, your driving style/habits wll be the largest factor here. Good driving - longer life. High RPM launches and power shifts - shorter life and more likely to see the cast pistons fail.