I think the rules and regulations are quite clear, anyone can upgrade their cars with bolt on parts from another same type of car without engineering (as that has already been done by Holden).
If your insurer has found that you have modified your car Illegally then your insurance policy will be void, whether the modification led to the accident or not.
Illegally?! What? It's a defect not a jail sentence. Unless you nicked the parts or bought them with the proceeds of crime...
I don't believe you are correct. Point to any evidence that suggests you are? You think if a piano was dropped from a crane onto my car they would void my insurance because I had HSV brakes on it?
If there was a defect with the parts used or the fitment and that caused an accident then the insurance company would probably still settle the claim and then come after you for the cash.