Using this rear diffuser is easy. First, gather all the mounting hardware that comes with the diffuser. Then, align the diffuser with the pre - drilled holes on your Subaru WRX or STI's rear bumper. Secure it in place using the push clips and screw/bolts provided. Make sure it's tightly fixed to avoid any rattling while driving. When it comes to maintenance, a simple wash with mild car soap and water will keep it looking great. Avoid using abrasive cleaners as they might damage the matte black finish. If you notice any loose parts, check the mounting hardware and tighten them up as needed.