Using this OLM rear diffuser is easy. First, gather all the hardware that comes with the product. Then, simply bolt the diffuser onto your Subaru WRX/STI 2015 - 2021 as it is designed to fit right up. As for maintenance, clean it regularly with a mild soap and water solution. Avoid using abrasive cleaners as they can damage the gloss black paint and the red line. When washing, use a soft cloth to prevent scratches. If you notice any loose bolts, tighten them up to keep the diffuser securely in place.