I've read the manga. The story in the video is similar to the story in the first volume of manga. I don't speak Japanese so I'll just introduce the manga characters briefly, you piece together the story yourself.
Akio : the guy dreamed of driving the Z, he took pictures of it when it zoom past the apartment. Later he found a wrecked Z in the j/y which happens to be the same Z(devil Z) he coveted earlier. The Z was owned by the architect girl's brother who died in a crash while driving the Z.
The Architect girl : "They repeat the scene of her in the Blackbird (the 911 turbo) like 3 times..." No, she was actually in the Z(when she is sitting on the left side of the car, she's in the Z, because the right side of Z is the driver seat). In the manga, the girl's brother often take her for a ride in the Z. She lost her brother when a car accident occured to the Z. Her emotions are strongly attached to her deseased brother(hence the scene of her in the Z to show her memory lingering in the past). In the manga the girl eventually forgets about the sad past and move on(moves to America to study)
The guy in 911 : In the manga he's a young doctor who was a close friend to the architect girl and her brother. When he found out the devil Z is running again, he set out to destroy it in front of the architect girl so the girl will break free from her memories. In the movie, the 911 guy doesn't get a lot of exposure.
The model girl : In the manga her name is Reina. She drives a white skyline R33 and developes a friendship/crush on Akio.
That's pretty much the story in the first vol. of manga(there are more than 30 vol. of manga) The story in the movie could be different.