Try this out:
Remember that calculations and math will only approximate things; experience is the only true measure. I'm sure there are guys running different turbos on the S52 that have posted numbers. Ask the Google.
Edit - where did you get this info: ".97 volumetric efficiency, which is pretty conservative"? Race motors can go above 1 at the right RPM range, but most street motors don't approach 1 from what I understand.