Sawa from Kite actually makes a two-second cameo in this OAV (At 5:28 through 5:30 of episode 1).
Two versions were released in the USA by Media Blasters: a "General Release" (rated 16-up) which was released by Media Blasters by their label Anime Works, and a "Director's Cut" edition (rated 18-up), which was released by Media Blaster's adult label Kitty Media which includes five minutes of footage not suitable for minors. In addition, an International Version was released in Japan on July 23, 2004. This version includes 20 minutes of extra footage, but none of the adult scenes found in the Director's Cut.
At the movie theater, while they are coming out, the two posters on the side are parodies of "Dirty Harry" and "Die Hard".
Behind Kurokawa's seat in the car, he has guns stored away there. The second gun is the assassin gun that Sawa used in "Kite".
The original USA DVD is available in both a stand alone version or with a XL T-shirt.