Last summer I was running SP8000s at 28 psi and my best 60ft's were ~2.1s. I didn't experiment that much though with different setups.
So you got those times with Stage 3 + 550cc injectors + the port & polishing... and that's it? Do you still have cats, or is your exhaust clean all the way through?
Way to go man!
Z-Jay Edmonton Z Car Club 93 300ZX TT - Stage V 01 Sentra SE - daily driver