Honda Civic FC450 Bumper Diffuser 2016-2021. Available at megamotorsports.pk. The Honda Civic FC450 Bumper Diffuser is a high-performance upgrade for your 2016-2021 Civic. Made specifically for this model, it improves aerodynamics and provides a more aggressive look. Increase your car's stability and enjoy a sleeker design with this precision-engineered diffuser.