Using this rear diffuser is easy. First, gather all the mounting hardware that comes with the product. Then, align the diffuser with the pre - drilled holes on your Subaru WRX or STI (2015 - 2021). Secure it in place using the push clips and screw/bolts provided. When driving, the diffuser will work to improve airflow under the rear bumper, which may enhance your car's performance. As for maintenance, simply wash it with mild soap and water regularly to keep it looking good. Avoid using harsh chemicals as they may damage the matte black finish. Also, check the mounting hardware occasionally to make sure it's still tight.