How much psi can stock internals hold?

[Shane@DBPerformance]

It could blow up at 5psi or 50psi. The boost isn't what matters the most. It will come down to power, tuning (timing and a/fs), and mechanical state of the motor. On pump gas though, you might not be able to run a crazy amount of boost. A DSM at 20psi on pump gas will usually also make way more at 20psi on E85 or race gas, just because of how conservative you need to go on the tune with pump gas.