many of the o4's mechanical components originated from the opel astra, a german small family car. the o4 had a 4-cylinder engine that produced , along with a manual transmission. the roof featured twin targa tops made of carbon fiber that could be stowed behind the rear passenger seats. in addition, the rear window retracted into a compartment located behind the rear passenger seats. the oldsmobile o4's doors have a manner of front conventional doors and rear small suicide doors.