The show's creators opted for a more modern and sleek design compared to the original KITT's Pontiac Trans Am, and chose to heavily modify the Mustang to resemble the classic Knight Industries Two Thousand (KITT) look.
However, the red color was never actually used for the car in the series. The production vehicle was always black, but the show's marketing and promotional material often featured it in red, perhaps as a nod to the original series.