So I just orderd a Slowboy Racing manual boost controller for my hatch and would like to know a safe boost level to match the mods on my car.

current setup: CA18DET (good compression)
S15 BB T28(wastegate pressure, 6-7psi)
Metal HG
FMIC
Blitz SS BOV
Blitz Access ECU
Blitz Filter
3" strait exhaust with 3" fartcan
Walbro 255 FP
z32 fuel filter
93 octane fuel ONLY!!!


Pretty much everything else engine-wise is stock including the injectors, MAF sensor, and I think the FPR is stock or non existant (I wouldnt know what it looks like or where it is if I do have one, let alone know what to do with it lol)

Im geting realy bored of 6psi of boost and would like to bump it up a notch or two, I just dont know of a safe maximum boost seting to work well with what I have. Im hoping I can get away with 9-10psi before having to upgrade injectors and whatnot but if not what do you all think?
Thanks in advance, it will be about a week before it gets here so if I left something important out tell me and I will let ya know. -Shane
P.S. What is the expected HP gain per PSI of boost added?