The Australian test was probably 0-100kmph (not 0-60mph) on an unprepared surface from a standing start (the US times let the have a little roll out).My apologies i removed the post, dont know what i saw, rewatched the video and saw the 3.9 :/
Im still surprised the US mustangs do a 3.9
The video below are reliable sources and the below 2021 GT A10 (From Australia) did a 4.9 so a second more then the US times
In Motor magazine I think it was a 2020 they tested and it got around 4.54 seconds 0-100.
That’s real world time which is not too far off the 4.3 seconds that Ford Australia advertised