In the beginning of the movie, when the baseball is thrown at Sean's car, it goes past him and lands on the passenger floorboard. In the next shot, the ball falls to the ground, with glass landing behind the rear tire, as if the ball had been thrown from inside the car.
During the Tokyo street chase, D.K. rams and bumps Shawn's EVO, damaging his Nissan Fairlady Z. After Han's RX-7 is destroyed, the Z has very few scratches or dents.
During the first race between the Monte Carlo and Viper, the starter pulls off her bra and throws it in the air. It lands about 10 feet in front of the two cars. Both drivers shift gears, accelerate for a few seconds, then drive past the bra, which is now 100 to 200 feet from where it landed.
During Sean and D.K.'s first race in the garage, the cars' lights are alternately on and off throughout the race.
When Han's car blows up, a character in the driver seat disappears when the flames rise.
If Twinkie was a military brat, his license plate would have a Japanese symbol that looks like a "Y" on the left side. Military members and their families with cars in Japan are required to have "Y" plates.
Sean's father is credited as "Major Boswell." When he is in Naval uniform, his shoulder board clearly displays the two full stripes of a full Lieutenant, and the collar insignia, while improperly gold, also has the two bars of a Lieutenant. The rank of full Lieutenant in the Navy is O-3. Major, O-4 is used in the Marine Corps, Army, and Air Force. The Naval equivalent is Lieutenant Commander. Major is denoted by a gold oak leaf cluster, not twin silver bars. A Lieutenant Commander in the Navy also carries the gold oak leaf cluster on his collar, and the shoulder board carries two full strips and one half strip between.
During Sean's first practice run in the Evo IX, a fisherman makes a snide remark in Japanese, translated as "You call that drifting?" The correct translation is "Counter-steer is late, huh?"
It's very unlikely for a Japanese high school student to own a car. Japan's driving age is 18, and the age of majority is 20. A high school student would need an adult signature to buy a car, or at least buy the mandatory insurance. Japanese teens who join motorcycle gangs, which are affiliated with organized crime, are often provided with stolen vehicles, which they generally drive without a license. The students depicted in the movie would appear to fit the bill. However, kids in motorcycle gangs usually leave school after ninth grade, the minimum leaving age in Japan, and rarely advance to high school.
The sign at the sheriff's department says Oro Valley was founded in 1919. It was actually founded in 1974.
If Sean doesn't speak Japanese, he would likely not go to a regular Japanese high school. American military kids can attend schools on base. He might attend a private international school, with Japanese and non-Japanese students.
When Sean first arrives in Japan, he carries a guitar gig bag. By time he arrives at his father's house, the bag is gone. (During a deleted scene called "All I Got" we see Shaun unable to pay for his taxi and ends with the driver keeping the guitar as payment)
Shortly after Twinkie's Volkswagen Touran "Hulkmobile" minivan is introduced, Shawn and Twinkie drive off. In the next scene, when the Touran enters the car park, a set of tires appear on its roof. In a deleted scene, Reiko and Earl steal tires from a gas station.
Twinkie appears to run a smuggling type operation, where he sells a wide range of goods (perhaps obtained cheaply on US bases). This is almost unheard of in Japan, where there is no shortage of legitimate retail outlets to purchase pretty much anything. Smuggled goods could be much cheaper than retail, since he presumably would not have to pay tariffs or charge sales tax.
When Han teaches Sean to drive his Evo on the pier, the camera zooms in on the right left tire. Sparks appear on the right of the screen, from the camera boom hitting the pavement.
After DK approaches and beats Sean, as he leaves, he's supposed to shoulder Twinkie out of the way. However, Twinkie actually puts his own shoulder into DK's to make it happen.
When the baseball goes through Sean's car window, the driver puts the car in park. The shifter could be mounted on the steering wheel, but it's not clear. The car has a clutch during the race, yet the floor shifter is semi-automatic.
When Sean, Neela, D.K., and Sean's dad meet after Han's accident, the camera is near the headlight of the Fairlady Z. Light circles appear for a few seconds, in the bottom right of the screen, where the lens of the camera caused distortion from the headlights.
During the chase, Han is t-boned at an intersection. The car is hit near the rear end, then begins to slide around. When the angle changes, the car is hoisted in the air, and the left side of Han's car comes apart like a paper bag, even though he was hit on the right side.
In every chase seen, the other cars in Tokyo are all moving at a snail's pace with plenty of space between them. This would never happen anywhere in Japan, where traffic is packed in such downtown areas and cars would travel as fast as the speed limit allows. It makes the scenes looked so staged as to prevent the suspension of disbelief throughout the movie.
When Han and Sean are in the RX-7 and talking, the engine tone shifts at least 7 times, as if the car has 7 or 8 gears, most of which have the same ratio and thus engine tone. Sean's hands remain on the steering wheel throughout the drive, yet the shifts still occur. In addition, they do not have the pitch a manual car would have (revs dropping from engaging the clutch, then shifting into the next gear). The two transmission choices for the car were a 4 speed automatic and a 5 speed manual. This is a recurring mistake in the Fast and Furious movie line.
Various boosted cars (such as the RX-7) do not make the signature sounds of upgraded turbocharged cars throughout the film, such as the turbo spooling and the blow-off valve, until they "hit the nitrous." Nitrous does not change the car's sound.
When Sean Boswell hits the nitrous in the Veilside RX-7, the rev counter shows the revs continually rising, but the engine sounds like the revs are maxing out.
When Sean races Clay, and parallels with the black truck, the camera and cameraman riding on his car are reflected in the truck's paint.
Extra reinforced roll cage seen in Sean's Monte Carlo right as he begins to flip over.
After the fiery car crash, Boswell rides the Los Angeles subway back to his father's apartment in Tokyo.
Outside the auto shop in Tokyo, the support columns of the Sixth Street Bridge in Los Angeles are visible in the background.
When Sean and Han escape Han's shop, they drift while trying to evade D.K. and his crew. They would have much better chance if they drove in a clean line, instead of drifting, which makes the car much slower.
Anyone still actively serving in the armed forces would not be allowed to live off base in Japan and certainly not be allowed to carry a weapon off base.
No yakuza of any rank in Japan would use a gun, dress in a full white "godfather/pimp" suit, wear a Panama hat, or be capable of speaking any English.
Despite being portrayed as the nephew of a yakuza boss and raised in Japan, D.K. speaks with a strong American accent, showing no clear Japanese linguistic influences. His few attempts to speak Japanese in the film are awkward and inconsistent with the proficiency one would expect from a native speaker.