On the stock turbo I ran 35psi + on stock head, stock gasket, stock bolts, ect... as long as you don't let it get to hot you will be fine.
On a side note after about 24psi you are just starting to push hot air. :wink:
Watch out for blowby too if its an older engine...I've blown the dipstick out a few times already. :roll:
Im looking to do the AAZ style crank case breather. Hopefully that will help.