During the final fight between Ma Jun and Tony, where Ma Jun is delivering knee strikes to the head while in side-mount position, Ma Jun's black T-shirt under his leather jacket is untucked. As the fight progresses, his T-shirt is shown to be partially or fully tucked in.
In the hospital after the explosion, Wilson yells angrily about the witnesses being killed before the sequence of scenes in which they are actually bumped off.
When the man is shot on the roof of the parking structure, even though the movie depicts events in 1997, there is a modern silver BMW 5-series parked next to the victim's car. It is a 2004-2007 (pre January 2007 facelift) model.
Even though the movie takes place around 1997 there is a BMW X3 a visible and the X3 wasn't available before around 2004.