Are the stock piston's forged?

Not necessarily. Anything can happen when you are dealing with forced induction. Just start with a rich tune,and low boost. Then bump the boost/timing slowly and see how it reacts. You MUST have a wideband o2 for proper tuning.
I work at a shop that has a Dynojet 224 with an eddy current and a wideband so I will tune it on the dyno under a load.