03MSP said:440's won't get you 16 psi on that, at least not at a comfortable AF ratio.
As for the 550's @ ~18 psi, I really don't know, but it isn't going to be a "sure thing" as I said before, I was just talking as if it were me (little turbo).
I'm running 15-16 PSI on my 460cc injectors, at close to a 50% duty cycle. This is with the GT-28RS. I will do another run to verify if that is what I remember..