When is it necessary to balance?/piston Q

[Inneedofabuick]

Iam in the beginning stages of a rebuild and sadly its put me in a bit of a tight spot money wise. I would like to get TRW forged pistons for 140 more but my question is would it then be necessary to balance the motor due to the weight of the pistons? If i have to pay the money to balance it then I will just go with hypers which the machine shop says shouldent need balancing because they are lighter than stockers. One more thing, any comments on the hypers?

Thanks
Matt