What inspection to you have to go through? I went for ID on the 4door and cos the car was missing a compliance plate they sent me for a roadworthy (not tier 3) passed the roadworthy with a bent rear subframe from the hit in the side. It's a pretty obvious bend but no cracks and the alignment can still be done to within specs.

For the ID, they don't get under the car or anything, simply check numbers and if the car is obviously defectable they'll refer you for a tier 3 same as the police would on the side of the road.

If you have a compliance plate, the car has been previously registered in Australia and it looks stock then I don't see why you need to spend the cash fixing up that crack.