the only mods that will increase the hp level over stock boost level/stock TT would be the freeing up of the airflow and finetuning the mixture...and a little timing tweak of a couple of degrees. The rest of those mods will allow for higher boost and hp of course but the above is true for your question. I dont have dyno figures to prove but I think it would be safe to say 20-30hp over stock at the wheels at same boost.
1990 Twin Turbo 5spd Stage 12+ No Show,All GO 1999 Maxima SE 5spd ..also performance modded