Shouldnt have any dramas unless you're having the same problem as I do. For some reason I was told during the tune the car cant hold the boost which is why I'm running 16psi. Anything more it wouldnt hold it. Was told high chance its a dodgy wastegate but anyway, back on the topic. My mod list is pretty similiar to yours except the turbos I have are N1 which I believe are GT-SS equivalent. No cams, using pfc and pfc boost controller kit. Got 255awkw for the tune running around 16.5psi. which is around 1.15bar. Having said that, with more fuel (bigger injectors, fuel pump), bigger AFM (Nismo, Z32 or just go map sensors) and more boost, I'm sure it'll go over 300awkw.