I'm in Sydney and in Wollongong every second weekend.
6 psi should get you around 100kw easy
Since the car is in Adelaide (right?) how did they get the 12psi tune?
Was it through the MS EBC? or a MBC/external box?
With Autotune you should have a driving map in about 1/2 hour.
You are welcome to a drive of mine if you like to see what 6 psi does (I killed the EBC)
