The van that is used for the diamond burglary says Falkore Plumbing on the side. Falkor is the name of the Luck Dragon that Atreyu rides in The Neverending Story. Atreyu was played by Noah Hathaway, who plays Fish in this film.
While eating fugu, Duke says "I cannot see her tonight. I have to give her up. So I will eat fugu." This is, in fact a famous senryu from Japanese poet Yosa Buson, written in the 18th century.