depends on what you're trying to do with the engine... if you want it to hold under anything other than NA, then save until you can afford forged pistons. if you're putting them in the starion, with the crappy fuel systems on those things i'd spring for the forged ones. it's hard to tune those cars well with the stock fuel setup so you're bound to get a bit of knock, and the cast pistons just won't hold up to that for too long.