I dont know why ppl think S15 turbos are any different.
There is only one model of the S15 turbo thats any different and the only difference is the Exhaust housing has a divider for the W/G
And it seems the P/N are different due to Tranmissions also
So if you have this part number, then you have an "S14" Turbo
If you have this part number then you will have an "S15" turbo with the divider: But that is the only difference
Max PSI is 16psi any higher and it will fail, I just had a customers T28 seize from boosting at 17-18 PSI