I did own an R34 gtr and my 34 was running pretty much an identical setup to yours and same boost with no issues as i was told the R34 turbos could actually handle more boost despite still being ceramic. I had stock turbos, 720cc injectors, walbro pump, power fc, profec b boost controller, 3" front pipe back exhaust and the car was great fun and tuner said that boost on factory turbos was fine. Never had an issue anyway. -7's should add even more fun for you :-)
Im currently in the process of getting an r33 gtr so just doing some research on its limits etc