It's funny that you say not many people outside of Linux/tech use that term when "ricing" started in car mod culture. It was used to describe the act of customizing your (typically Japanese import, hence the term "rice") car with an abundance of cosmetic mods, without investing in performance mods. So your car would look really sleek and custom on the surface, but it would still drive like a stock '94 Honda CR-X del Sol.

Before anyone asks: "race inspired cosmetic enhancement" is a backronym, not the origin of the phrase.