Revealing mistake: Leonardo DiCaprio blinks after he dies. (01:50:28)
Revealing mistake: When Benvolio is running away from Tybalt and the fire, there are two Policemen visible who could be doing something about the gunfire etc. My guess, not supposed to be in view. (00:07:55)
Answer: A lot of the cars can be found here - http://www.imcdb.org/movie.php?id=117509.