Factual error: Dom makes fun of Brian after winning Brian's car in the first race scene. Dom says that Brian was "Granny shifting, not double-clutching like you should." Double-clutching is primarily used by truckers that don't have good synchros on their transmissions or road racers that need to match their transmission speed to the engine speed while downshifting through turns. Granny shifting is upshifting while revs are still low, a technique used to prevent traction loss with powerful torque cars (though it's rare and generally unnecessary). The writer, who is absent of any true racing or automotive knowledge, may have been thinking of power-shifting when he wrote Dom's lines, but the two types of shifting are NOT interchangeable and Dom saying such a thing is a mistake.
Factual error: During the first race a square plate on the floor falls off Brian's Eclipse. The Mitsubishi Eclipse is a unibody car; the frame and body are built as one solid piece, and it does not have floor pans. While some racers might put a steel plate in the interior as a finishing piece, it would be cosmetic only and not part of the vehicle's structure.
Factual error: In the first hijacking, one of the Honda Civics slips under the truck's trailer to avoid the road crew. Trailers with that much ground clearance do not exist. The trailer has been modified to ride much higher than normal to make this stunt possible. The modifications to the lowered Honda are not sufficient to fit beneath an un-altered trailer.
Factual error: In the beginning of the film where Jessy is looking under the hood of Brian's car he says he has a T4 turbo. On NON turbocharged Eclipses, the intake is routed along the driver's side of the engine, which you can see (the big chrome tube). On the turbocharged Eclipses, the intake is on the front passenger side and routes to the passenger side of the engine to the throttle body near the fire-wall. Non turbo Eclipses have the throttle body on the driver's side.
Factual error: When Brian tops out his Eclipse, it spins out. A car should not spin out at top speed. A car will either reach a drag limit or, in this case, hit the engine's fuel cut off, and should continue straight. He did not jerk the wheel to make the tires lose traction, nor did a tire blowout. Imagine if a magazine editor tested the top speed on a Viper, he would be spinning from 186 MPH. No one would be testing top speeds on cars if this event occurred.
Factual error: Brian tells Dom that hector is running spoon engines with T66 turbos and a motec system exhaust. Spoon engines are typically 1.6L and are a terrible drag racing choice, also a 1.6L engine cannot properly spool a T66 turbo as the exhaust gasses do not have enough pressure to effectively spool the turbo.