During the duct tape death match against Shingo, Takumi binds his right hand to the steering wheel, however, as he takes a corner, about halfway through the race, a shot of the steering wheel shows both hands free.
Kenji's 180SX fastback changes from white to red in various scenes.
Takumi's AE86 front bumper badge changes from "Trueno" to "Toreno" throughout the series.
During his race with the 86, Kenta's S14 changes color from orange to black and then back to orange again.
In his race with Shingo, Takumi clips a corner, audibly smashing off one of his rear lights, yet the next shot shows the back of his car with no visible damage.