I'm in a simillar situation as you, r33 with t3/t4 unknown turbo hybrid which came with the car when bought and hits max boost pretty late..
in my car positive pressure starts to build at between 2000~2500, 10psi@ about 3000 and reaches full 16psi at about 4000rpm.. puts out about 240rwkw
thats with pfc and electronic boost controller tuned, z32 afm and nismo injectors...
its not the mose ideal power delivery curve, a bit more response can probably be had with a more aggressive tune with more IGT, but can't really complain since i dont know the specs of this turbo, all i can see/tell is it uses factory exhaust housing and new intake housing, and i'm suspecting its probably a budget turbo...
so yes.. assuming we have simillar or even the same turbos, this is what a tune with proper supportive hardware can get you