KITT was a very modified 1982
Pontiac Trans Am. Among the modifications: An inset sequentially-flashing red lightbar was installed in the front of the
car to represent KITT's
sensor array. The interior of the car was
extremely modified, with a totally new dash and
steering wheel, a
groovy gas pedal with
LEDs up the side that lighted up sequentially as the pedal was pressed, etc. KITT had many cool features, including a
laser that emanated from his sensor array *,
turbo boost (which allowed him to jump over anything in his way),
super pursuit mode (jet engines, huge spoiler, fast fast fast, 'nuff said), ejector seats, etc. In two episodes, KITT battled his evil twin,
KARR (Knight Automated Roving Robot).
*Accipiter informs me that the laser actually came from underneath the front bumper. I was ten years old when I last watched the show, so my memory's pretty hazy.