When George is sharing a cell in prison with Diego, George is seen reading a paperback while reclining on his top bunk. The book is "Hells Angels" written by Hunter S. Thompson, the author whom Depp previously portrayed in the movie Fear and Loathing in Las Vegas (1998).
When George is in the courtroom the first right before he finds out that Barbara's sick, the words that he is reciting to convince the judge that he is innocent are lines from Bob Dylan's song "It Ain't Me Babe" and Woody Guthrie's song "Pretty Boy Floyd".
A lot of Johnny Depp's dialogue was improvised, including the scene where they are trying to find a place to put all their money from selling coke and his line "We're gonna need a bigger boat" (a quote from Jaws (1975)).
The scene at the hotel (where Johnny Depp gets shot in the shoulder) was supposed to be taking place in Miami Beach. It was filmed at a small hotel outside of downtown Los Angeles, where it was raining and about 40°. Shooting had to be delayed briefly because the actor's breath could be seen on film.
According to the Director's Commentary, the tape that George Jung leaves for his father near the end of the movie is a verbatim transcript of a tape that the real George Jung recorded under similar circumstances.