The Volvo next to the blown up limo (after the explosion when the police and bomb squad are on scene investigating) is the same model and even bears the same license plate as Sharona's.
The regular theme tune is rapped by Snoop Dogg.
When being introduced to Murderuss and his crew, Adrian does not once ask for a wipe after shaking the crew's hands.
When Monk is visiting the site of the car bombing, he tells the Bomb Squad officer where two of the blown-up car pieces would go, adding: "You do the corners first." This is a reference to how to start putting jigsaw puzzles together. Monk loves to do puzzles and is very good at them, as seen in "Mr. Monk and the Employee of the Month" (S3 Ep 7) and "Mr. Monk is at Your Service" (S5 Ep12).