I wouldn't spend money on a hypermax they leave a good bit to be desired
Idiperformance.com also sells new turbo kits.
If r&d is too much I would look for a used turbo kit and depending on condition have the turbo rebuilt.
Used kits can be had for about 1000
My preference is ats 093 or factory turbo kits as they are almost identical. The most prevelant and have the most aftermarket support available
Yes Nero is accurate anything over 12 psi studs should be highly considered
Under it especially on a 7.3 don't worry about it
Definitely agree to skip the hypermax. IIRC the turbo platform is proprietary and non-upgradable.
Wes at CDD also has full kits. Not sure what your budget is but new hypermax kits are $2700+. Same coin with Wes gets you better everything and especially a much more efficient and modern turbo.
Also comes with a 3" downpipe that will wake up the beast. Stock DP hurts it even at low boost levels due to restrictions.
From what I've read Justin has an equivalent setup at R&D.
I would recommend you re-torque the head bolts, it was actually a Ford factory service adjustment at around 50k.
But it's a great idea for running boost. I've gotten up to 15psi, 14 sustained and aftercooled. Gives great peice of mind to know they are torqued correctly-- I had a bunch of coolant weeping at the back corners and this all but fixed it. I lose almost none these days.
As I re-torqued I found some of the head bolts were nearly loose and didn't take much to break free. (You break them loose 1/4 turn then torque to spec. Then go back over everything again, all using the correct sequencing pattern.)
Bear in mind that 4psi of boost on any stock style platform-- Banks, Hypermax, or ATS-- will have no real gain over a well-running N/A. The OE Ford turbo (made by ATS) system gained like 5hp/10ft-lbs over stock at 5psi of boost.
FWIW a turbo with 3" downpipe is the best mod ever. Next best is charge air cooling. It takes the same compressed air and makes it more dense so more fuel can be used, without making more danger to blowing head gaskets.