Using these mirror trim overlays is a breeze. Just clean the area on your WRX/STI's mirrors where you'll attach the overlays first. Make sure it's dry and free of dirt or dust. Then, carefully stick the overlays in place. When it comes to maintenance, a gentle wipe with a soft cloth and some mild car cleaner every once in a while will keep them looking great. Be careful not to use any abrasive materials that could scratch the carbon fiber. Also, avoid exposing them to extreme heat or cold for long periods, as this might affect their adhesion.