When Vince Vaughn slaps Snoop Dogg during the golfing scene, it was actually unexpected the first time. Todd Phillips said, "Snoop went on with the scene and then when it ended he said, 'What the hell was that??'."
Todd Phillips was having a hard time finding a blueish 1976 Lincoln for Huggy Bear. When he revealed this to Snoop Dogg, he was surprised to learn that Snoop actually owned a car of the right color and it's his car that appears in the movie.
Originally, Todd Phillips wanted the knife-throwing scene to feature ninja stars instead. But the idea was scrapped when learning that any scene featuring ninja stars would automatically get an 18 Rating in the UK.
The "New Coke" pushed by Reese is supposed to spoof the alternate formula Coca-Cola introduced in the 80s. When Coca-Cola premiered its original soda, the ingredients included cocaine (it was removed in 1903).
When filming the yacht scenes with Vince Vaughn, director Todd Phillips became very seasick and mentioned that he hated boats. When asked why he included one in his screenplay, he vowed never to write/shoot a scene on boats again.
One of the outtakes shown during the closing credits (the scene with the undressing cheerleader) has Starsky (Ben Stiller) blowing on Hutch's (Owen Wilson's) face to get his attention off the nude girl. This was a reference to a strip club scene from Starsky and Hutch (1975), used in the opening credits of that series.
About 10 1975-76 Ford Gran Torinos were totaled during production. Only two Torinos from the film were intact. One of them is a genuine 1976 Gran Torino with the Starsky and Hutch (1975) paint job, and the other was a base 1974 Torino which had been in storage. In reality, the 76 and 74 Torino which was used in the film was repainted with the white stripe resembling the one used on the TV show. All of the movie Torinos used 15-inch slot mag rims. They're not available new, so the rims (originally known as the Ansen Sprint, first introduced in 1963 and subsequently copied by several aftermarket wheel manufacturers e.g. E-T Wheels, Appliance, Cragar, Fenton, American Racing, U.S. Wheel) until the early 1980s) mostly came from swap meets, salvage yards, or eBay.