14 psi on what turbo though???
It is not the psi level but the airflow at said psi level. Just a psi rating means little to nothing without airflow numbers.
14psi on a T3 40 trim would barely get you moving but 14psi on a T66 would likely pop the stock head bolts...
Either way forged pistons & rods will easily support 14psi on a T3/4 60-1 trim and that would be my guess as to what you are running (if you are building a 3L too) Otherwise I'd guess it's a 54-1 with a 2.5L
Heck the stock rods are stronger the anyone believes and will take more abuse then the stock pistons and the revised pistons should support a max of 450 crank HP or so. (400+ is already a known given thanks to TOM)
For instance I think a full oval port 3L at ~9.7CR (~$1200 if you can do the labor) should do nicely and safely with a T3/4 60-1 trim and large turbine wheel at 8-10psi (330-360FWHP/TQ)
That's already far beyond the level of power this platform can handle in the first few gears.