I say 8psi for two reasons. 1) stock rods don't like more than 8psi for very long at the factory rev limit 2) with regular 93 pump gas, my personal limit on boost without a cooler is 8psi.Kind of what I’m thinking although it’s already on 10psi. Still runs like a dog though.
Ideally, get a cooler though if you can. It's just smart. A 170° thermostat with adjusted fan on/off settings in the tune could help save your bacon too.