All of the wardrobe and costumes are vintage late 70's and 80's found in thrift stores, Goodwill, and Salvation Army outlets.
The plant Carol that Karl had as a companion had a stunt double named Carolita. They are a species of Variegated Snowflake Bonsai plant related to the Parsley family.
The thugs' car in the film is a '76 Brougham.
Karl's car is a '73 Mustang. The first body change from its iconic first design.
The science behind the movie is based on real science for the era.