Firstly I call bullshit on the "120rwkw 4AGZEs running stock boost". It just isnt going to happen.
Basically your engine is fairly stock and so will make fairly stock power. 80rwkw being a little low, but not embarassingly so. The exhaust may help things a little and the ECU will let you tweak things for a little more power, but neither will set the world alight.
If you want to see good results up your boost. Fit a big crank pulley (forget about your water pump it isn't an issue), SC14 and/or late model, smaller SC pulley. Opening up your throttle and inlet can also help. 3SG throttle has been documented, intake manifold is more involved and probably not as beneficial. And cams will help the show out too, around 260-270 is what I'd recommend.
And yes, a dyno figure isn't the be all and end all. Look more at your AFRs and make sure they're safe, and ensure your tuner knows how to get the ignition timing right. This can have a big effect on the power.
Hen
NB, adding bigger injectors will not make an engine make more power UNLESS the old injectors were the limiting factor. Intercoolers follow a similar rule too.
