Our newest s197 rear diffuser fits California Special and GT500 Mustangs. This is our first rear diffuser made completely from ACM and matches our other aero products perfectly. As with all of our diffusers, in the event of damage the Fins are easily replaceable with screws going into the top of the fins giving our diffusers a very clean appearance. Purchase includes all mounting hardware. Installation of this diffuser does require CUTTING out the factory diffuser.