In the final race, Maggie is seen to climb into the car via the window, this suggests that the doors have been welded shut to improve the structural integrity of the car, common with many forms of track racing. However, after the race is finished, Herbie flings the door open to knock Kevin closer to Maggie.
After the second race when Herbie purposely brakes to let the other person win, when Herbie is being towed away, there is a shot from Herbie's point of view looking at Maggie. In that shot, Maggie is facing Herbie. In the overhead shot, Maggie has rotated 90 degrees to the right.
About an hour into the film, as Herbie's being pulled away on the tow truck, we can see from his point of view that Maggie's helmet is lying on the ground several feet in front of her. This makes sense as she threw it on the ground and walked a bit away from it a few minutes earlier. However in an overhead shot, the helmet has moved next to Maggie, although she's still standing in the same spot. Also, while Herbie's being pulled away, the fan stands inexplicably disappear leaving Maggie and some fans standing in the middle of the desert.
Herbie has been modified before the demolition derby to include a spoiler, an updated engine, side air vents, bucket seats, a sound system, nitrous-oxide, numerous new gauges, and what appears to be a blue window over the engine. When Herbie is towed away and put into the derby all modifications have disappeared - as if they were never made. This is also true when Herbie is recovered for repairs.
When Maggie loses hope during the big race after getting boxed in by the other cars, we see her team bow their heads. The movie then immediately cuts to a shot of her in the car saying, "I'm getting killed out here. I can't shake them." The very next shot is of her dad with a headset on standing among the team (in between Ray Peyton Jr. and Kevin). He wasn't standing with them when they bowed their heads three seconds earlier and there wasn't enough time for him to have walked up, put the headset on, and stand there so calmly.
When Maggie first enters Herbie, she closes the door and the glove compartment falls open revealing an envelope. When reaching for the envelope, we see three black bracelets dangling on her wrist. When she puts her hands closer to the steering wheel to read the note inside of the envelope, the bracelets have disappeared. We see about five minutes later that she now has at least 10 of the same style bracelets on.
At the NASCAR race, we see Herbie's oil tank leaking. Kevin asks Sally if she has an extra oil tank. We see the tank replacing the other one. Yet when Trip is pushing Herbie up against the wall, we see the oil tank leaking again. It is actually the same one used before the replacement.
The first time we see Herbie at the California speedway boxes, when he is taken out the truck, he wears two stickers in the front side of the front mudguards near the headlights. In the following scenes and the race, the stickers are in the back side of the front mudguards.
At the end of the last race, when the 82 flips, the 24 spins also, blocking the track. Herbie uses the fence to get by. After he crosses the finish line, they pan back to the rest of the cars. All the cars are still at full speed, against the wall, two wide, and the 24 is in the first row on the outside.
When Maggie is taking Trip's stock car for a spin, Trip checks Herbie out. In one shot, they used street racing Herbie, in the shot where Herbie pulls a silly face on Trip, they used NASCAR Herbie, the next time we see Herbie, hes street racing Herbie again.
In the final race scene, Maggie's hair goes from in front of her face to behind her ears when she first puts on her helmet, with no time for her to have made the change. When she wins the race and removes her helmet, her hair is still behind her ears, yet, when she stands up to face the crowds, her hair is over her face again.
In the final race scene after the oil pan replacement, we see a shot of Herbie passing the Lowe's car. However, not two seconds later we see a rear shot of the Lowe's car. The announcer said "Herbie is passing them left and right" but this would not be continuous if the Lowe's car passed him back.
In the very last scene, where Herbie is going on a date with the New Beetle, a person in a black suit can be seen sitting behind the wheel of the New Beetle, with their hands going across the steering wheel.
During the NASCAR race, when Herbie starts leaking oil by the cylinder head, the team gets the spare part from a New Beetle. The Volkswagen Type 1 has an air-cooled 4-cylinder flat engine. The New Beetle has an liquid-cooled line-4 engine.
During the race at California, Maggie and Trip violated a NASCAR rule by wearing open-faced helmets. NASCAR banned open-faced helmets after the death of Dale Earnhardt. Jimmy Spencer and Dale Earnhardt Jr. were two of the last drivers to wear them.
At the beginning of the film, when the junkyard men were trying to remove Herbie from the truck, Herbie sprays oil on the foot of the junkyard owner from the front hood. The oil pan, like the engine, are in the rear of the older model VW Beetles, not under the front hood.
When Herbie is in the demolition derby, Crash sprays red circles (a bullseye) on Herbie. He sprays the front hood only, but in the next shot there is another red circle on the driver's door, which hasn't been sprayed. On the DVD there's an extended demolition derby scene which shows Crash spraying the driver's door. Though not part of the finished film, this scene can be inferred to have happened but not been shown because it wasn't interesting enough.
When Maggie gets to drive Trip's car, it's supposedly night time. But the headlights, while clearly shining brightly, are very dark. The shots were clearly filmed during the day, then darkened to look like night.
In the scene where Maggie and the two Rays are driving home in the green pickup truck, the model of truck is a Chevy Silverado which has a column mounted gear lever. In one shot, you can see the top of the lever which means it's in the Park position.
When Herbie is on the back of the truck in the wrecking yard, he spins his rear tires in an effort get off the truck bed. You can see the dolly wheels holding the tires up enough so they will spin without the car going forward.
When Maggie and Herbie race Trip the first time, after Herbie "mirrors" his car, there is a moment when Maggie grabs the gearshift and lightning flows down the shifter followed by some animation of gear action going forward from the shifter. In a (real) Beetle the transmission is located under the back seat, right in front of the motor and the shift mechanism is a rod going back to it.