We paid all the duties in full at the time of import, the car could then be sold on whenever, maybe thats changed since, although I think that may have been a very old rule rather than a new one.

Our 3dr is still in Aus, the current owner is on PF and has converted it into a very high spec track car.

If you cannot take the car in under the personal import rules I honestly would not bother, sell it, buy an aircon equipped ST and go the SEVS route.