Here's some trivia from IMDb...
The Lotus Esprit underwater spy car had the following features and gadgets: A periscope; convertible dashboard-control panel; oil release, harpoon and cement guns; retractable turning wheels; hydroplanes; protective louvres; television monitor; rudder and propulsion units; submarine activator; rocket missiles and missile firing control.
The Lotus submersible (the Lotus Esprit underwater car or Lotus submarine car) was code named Esther Williams in an early draft of the script and was also nicknamed by the crew as Wet Nellie (after the mini-helicopter in You Only Live Twice (1967)).
After the film's release, demand for white Lotus Esprit cars surged to the point that new customers had to be placed on a three-year waiting list.