In NSW the tare weight used to calculate engine swaps is taken from the heaviest variant, so use the wagon weight when converting (around 780-790 from memory).

There was a dude at the Ettamoggah on Sunday who had an SR20DET ute. I asked him how he got it engineered, he said it was an old conversion done before the RTA changed the regs to their current format.

If you live in NSW and want one just take it down to Canberra to have it engineered. Apparently that's how mst people get around the NSW laws these days.