Insurance during shipping
Where possible J-Spec uses shipping lines which offer insurance against loss, damage and theft while cars are in transit, and this is provided free of charge. When the car enters the port in Japan a survey of the condition is done, and when the car then leaves their care in Australia a survey is done again to ensure that the car is in the same state when it leaves as it was when it arrived. If there has been damage or theft of parts during transit then a claim process can begin to replace the stolen parts or repair the damage (note there is an excess). If a car is damaged or has parts stolen at other times (for example while in transit within Australia) then this is the responsibility of the party involved (such as the truck transport company) and the issue should be taken up with them.
Damage or theft is relatively rare nowadays and is far less common than rumours would suggest. Several years ago this issue (particularly theft of aftermarket parts) used to be far more severe and so this is why these rumours persist, but nowadays it is not a common occurrence. In particular since less heavily modified vehicles are now typically imported, and steps at the port in Japan (with some pushing from J-Spec over the years) have been taken to reduce risk. The most common parts which do get stolen are anything easily removed (e.g. gear knobs, aftermarket gauges held on by tape) and anything which requires unbolting or a bit of work to remove is pretty unusual to go missing. The most common damage to occur is normally scrapes to bumpers, particularly of very low vehicles.