Custom Style Rear Spoiler by SEIBONÂ®. Give your car a high-tech aerodynamic look with this carbon fiber rear spoiler. Besides looking great, a rear spoiler can increase downforce for better traction. Whether you're a racer or just want to look the part, you can depend on SEIBON for style, performance, light weight and durability. SEIBON components are carefully hand-crafted using only the finest materials.