Mine runs at 12psi boost but non-intercooled. Yours at 8 psi may be the same net boost with an intercooler.
For more power there are other things to can do also.
I don't know if you would have do any mods other than adjust the boost.

But if you are after more power add a 2.5" exhaust system from the turbo back. The turbo then comes in earler and the engine pulls harder.
You can crank up the fuel delivery, if it starts smoking it's to much.
You can advance the timming in conjunction with the fuel crank.
A couple guys over here have done just that with a dynotune for the fuel and timming advance and report a change of 117hp to 150hp and 225Nm to 320Nm at the fly wheel with these 3 changes. This is for the non intercooled 4JB1-T

I've done the 2.5" exhaust system and yet to do the rest but already it feels like a differant vehicle.