Canon Welding: The villainous businessman in Rides Again, Alonzo Hawk, was previously the villain of The Absent-Minded Professor and Son of Flubber, and is played by the same actor.
Franchise Killer: Fully Loaded's mixed reception combined with Old Shame, see the YMMV page, might have been this.
Velma is the female hippie in the car Jim "races" with Carol.
Keep Circulating the Tapes: The 1997 film and the CBS miniseries were released on VHS but never on DVD or Blu-ray. Torrents on YouTube or other websites can be readily found.
The very reason that Maggie buys Herbie in the first place is because she needs a cheap ride for her last month in town. In The New Tens, it would have been far simpler to simply rent a car for a month or use Uber or a similar service whenever she needed to get around.
The climax has NASCAR. That's not so bad on its own but several factors; the car types, the announcers, the drivers; lock it as a product of the early 2000s.