Using this Noble Yane San Carbon Fiber Roof Spoiler is easy. First, test fit the part on your 2015 - 2021 Subaru WRX/STI to understand how it fits. It's better to have someone help you with the installation. Make sure the temperature is between 75 - 95 degrees and the humidity is low. Clean the area where you'll install the spoiler to get rid of dirt and debris. Apply 3M tape to the outer edge of the spoiler. Pull up a corner of the adhesive backing strip. Place the spoiler on the rear glass, align it, and then pull out the backing strip. Press firmly on the spoiler. Wait for at least 24 hours for a strong bond to start forming, and it will be at full strength in 72 hours. For maintenance, keep it clean by washing it gently with car - friendly soap and water. Avoid using harsh chemicals that could damage the carbon fiber finish.