Since Annie Wu didn't speak Cantonese at that time (she was just learning the language), all of her scenes and those of Uncle Seven and his family (including Jackson Lau) were done in Mandarin. Thus, most of this film was shot in Mandarin, not Cantonese.
Most of the vehicles used were provided courtesy of Mitsubishi Motors. In the beginning, there are several Diamantes, Galants and a couple of Lancers. Near the end, they showcase the GTO Twin Turbo convertible (3000GT VR-4 Spyder). Also, there are a few Hyundai vehicles, some of which are manufactured by Mitsubishi.
The only Police Story film in the original quadrilogy that never received an American release by Dragon Dynasty. This is primarily due to Dragon Dynasty having the rights to the first two films via Fortune Star, and then using their previous Dimension Films cut of Supercop for the third. In fact, aside from Japan, New Line Cinema parent company Warner Brothers owns the international rights to the film.