Biff Manard was actually drunk while playing Hap Ashby, and Tim Thomerson had to literally man-handle Biff because he had no idea what he was supposed to be doing or where to go.
The pro-ball tooth that Ashby spits out was Biff Manard's actual tooth. Tim Thomerson gave Manard money after the shoot to get the tooth repaired.
Jack Deth's car is a 1955 Mercury Montclair that was heavily modified by Gene Winfield, who built the spinners and full-sized cars for Blade Runner (1982).
Tim Thomerson had personally recommended both Helen Hunt and Biff Manard to the filmmakers.
At the time of "Trancers" release, one of the marketing assistants who had just started working for Empire International Pictures was future actor Greg Kinnear and "Trancers" was his first film that he was assigned to help promote it for the studio. 13 years later when Kinnear eventually became a full-time actor, he would co-star with Helen Hunt in "As Good as it Gets" which Hunt won the Best Actress Oscar and Kinnear nominated for the Best Supporting Actor Oscar.