hey mate. i am/kinda in the same boot as you are with my 34. heres is the thread i started http://www.skylinesaustralia.com/forums/Next-t255192.html
iv only got a few liitle things more then what you have.
i presonally will ditch the AVCR get a PFC which is around $1400ish, followed by injectors (600cc would be looking at $900ish), cam gears and get that tuned up. that should see you with good gains. then dtch the stock turbo for a high flow one or something bigger.
i pretty much have all of the above except by injecteros are only 480cc and thats seeing me at a safe 240rwkw till i get cams and bigger injectors running 16psi.