AMF
Mmm...

I'm leaning towards a turbo for sure.

I'm perplexed about the Bathurst...
It was apparently the base model, but nowadays they're approx. $4000+ more expensive than most others...
What's so special about them now?

(Besides the "Bragging" rights to say - "I own a car made for Bathurst")

Simple really.
By far the most common SW20 you will find is the '90 model that had the Gen2 motor.
Bathurst models were later models ('94 on)  so probably don't have as many k's.
But the main reason could be that they had the improved Gen 3 improved motor.
They were also lighter and go harder.
It may help if you do a bit of Googling to find out more.