well im not a turbo stang, but im sc. I think the prob. youre referring to is compression.
its not the actual pistons themselves...its the compression which comes to be a problem. compression you want to run varies accorfing to the boost you want to make. Too much compression and youll blow something, most of the time head gaskets. Too little and you wont make as much power as possible. Dished pistons are a way of reducing compression ratio. it also has to do with the heads you run (combustion chamber size) and gaskets you use. I couldnt tell you which exact set-ups make what compression ratios, but im sure you can google n find more info on what set-ups will make what compression.
someone may correct the information i have, but im pretty sure thats compression is what youre referring to.