Four of the actors from this movie - 'Mako', Dante Basco, James Hong and Clyde Kusatsu - would work together again in Avatar: The Last Airbender: The Storm (2005), in which all four voiced characters.
When "Jeff" is fighting the gang of thugs in the antique store at the beginning, he knocks the guy through the window (same one he pulled through at the start of the fight). When the guy is shown landing, there is a glimpse of a blue landing mat just outside the window.
When Jeff and Adam are chasing Tanaka, Tanaka hits a truck with his car. Another car falls on his. In the car that is on top, the crew is reflected in the front window.
when Jeff's fighting in the warehouse, he beats up about six people. One of them has a red bandanna on, which gets knocked off. In the next frame, the bandanna is back on the guy's head.