to new cadillac convertible

one of the things that suck about this movie is that the cadilliac convert
that the films bad guy drive is like 4 years newer then when the movie is supposed to take place, i hate things like that if you are going to shoot a movie supposedly in 1964 why have a (i belive it to be) 1968 car?
(i am very sure it aint a 1964 or earlier car atleast!!)