lil jun stock boost for a rb20 turbo is 10psi well mine was.. i've got the s1 33 gtst turb on mine thats why im running 7psi
stock turbo shouldnt die at all on stock boost..
12psi is the max i'd recomend for the stock ecu with the rb20 thats the max i'll be running on mine untill more mods happen (computer, etc)