The Fleet-X was designed to be as light as possible, substituting polycarbonate for the rear quarter and tailgate windows. The concept used different colors to identify where lightweight alternate materials were used, including the exterior door skin, hood, and roof panels.[1]
"Global Concepts: Subaru Fleet-X". Automotive Engineering International. SAE International. 1999. Archived from the original on 18 February 2005. Retrieved 25 May 2017.