BMW may have done it first, But Toyota follows suit on the custom Gen III
Prius, "Aerius," at SEMA 2009:
"A unique body kit and 19-inch alloy wheels (covered with clear covers to
reduce drag) help maximize economy, too."
Aerius_thumbnail.jpeg
I can't tell exactly how it is attached; something to do with the blue ray-like
things I guess.
SEMA 2009: Toyota Prius Aerius Concept