The Mercedes that chases Paul and Ben had to be modified for filming, since that brand of car does not swerve very well in high-speed pursuits.
When Robert De Niro is singing "I Feel Pretty", the lyrics used are those from the original stage version, as opposed to the film version of West Side Story (1961). The lyric "I feel pretty and witty and gay" is changed back from "gay" to "bright".
Paul's main nemesis is named Ragazzi, which in Italian means "boys".
The casting of Joseph Reidy, the actor playing the Assistant Director ("AD") who gets fired in the movie-making scenes within Analyze That is an in-joke. Joe Reidy is, in real life, a professional AD and is considered to be one of the best ADs in the business.