Using this OLM rear diffuser is easy. First, make sure you have all the installation hardware included in the package. Park your 2015 - 2021 Subaru WRX or STI on a flat and stable surface. Clean the area where the diffuser will be installed to ensure a good fit. Then, follow the step - by - step instructions to attach the diffuser using the provided hardware. As for maintenance, regularly wash the diffuser with mild car soap and water to keep it clean. Avoid using abrasive materials that could scratch the paint. When driving, be careful of speed bumps and rough roads to prevent damage to the diffuser. If you notice any loose parts or damage, check the installation and contact the manufacturer if needed.