Northern suburbs go for CREATD motorsport; fantastic tuning by Rob on my r34 gtr vspec 2.
500bux for a full 4wd tune.
if you truely have n1 turbos you will make close to 300awkw as my car made 255awkw with only stockers, ebc, catback and pods.
make sure you run your engine in first though!!!
you wont be disapointed if you go to CREATD; i was blown away with the modern equipment and best service ive ever recieved at a tuner.