- The Other Darrin: While most of the cast reprised their roles, several got recast:
- Lightning is now voiced by his substitute voice actor, Keith Ferguson, instead of Owen Wilson, who voiced him in the movies and the first game.
- Doc is now voiced by Corey Burton instead of Paul Newman.
- Scott Wood replaces George Carlin as Fillmore.
- Audrey Wasilewski and Anna Graves replace Lindsey Collins and Elissa Knight as Mia and Tia, respectively.
- During his short cameo in the credits sequence in the first movie, Billy Crystal reprised his role as the Mike Wazowski car. In Mater-National, Mike is instead voiced by his usual substitute actor, Carlos Alazraqui.
- Role Reprise: John Goodman reprises his role as Sulley.
- What Could Have Been: There's so much cut content, the World of Cars wiki has an entire page dedicated to it.
- Various NPC racers such as Mia (and by extension, Tia), Fletcher, Philip, Yuri, Lenny, Snot Rod, Judd, Buford, Lewis, and former playable racers Sheriff and Count Spatula all have playable data for races and minigames, hinting that they may have been intended to be playable at one point or another. Snot Rod also appears in the intro movie being driven from the player's perspective, lending further credence to this theory.
- Gudmund and Koji were originally called Sven and Hiro, respectively.
- Tommy Joe, Fred, Philip, Yuri, Emma and Snot Rod may have been intended to drive around on the story mode maps, if the unused voice clips involving them greeting Lightning are any indication.
Trivia / Cars: Mater-National Championship