srp pistons are 4032 grade aluminum, the je pistons are available with the much desired(and the ones i have in a nitrous application)2618 for harsher environments with more cylinder pressure,nitrous blower and turbo stuff
i have them and no probs sofar,i got them through flatlanderracing.com(if memory serves me correctly)motor is a dart 572.
srp pistons are not ment to be used with much over 200 horsey power hit of nitrous.