I had wondered how many cars were equipped with power vent windows (when they were optional)and had assumed they were not that popular. My parents 68 SDV was bought from dealer stock and although it was well-equipped (vinyl roof, leather interior, AM-FM Stereo, tilt/telescope wheel, Automatic Comfort Control, Guide-Matic headlights, disc brakes, six way seat,power doors locks,tinted glass, WSW tires, trumpet horns,door edge guards)it did not have power vent windows, cruise control, Twilight Sentinel, or Controlled Differential. I was amused at Cadillacs description of the optional disc brakes that year: "Disc brakes are offered as an extra-charge option on front wheels for those drivers who prefer them". I guess those drivers who prefer them were only those who wanted to stop quickly and with less fade.