These fender emblem inserts are a great way to spruce up your 2015 - 2021 Subaru STI. To install them, you'll need a toothpick. Start by cleaning the area where you'll put the stickers. Make sure it's free of any debris or wax. This will help the stickers stick better. Use your fingers and the toothpick to place the pieces in the right spots. The toothpick is handy for pushing and guiding the vinyl. Go around the corners and the center of the vinyl with the toothpick to make sure it's firmly attached. As for maintenance, keep the emblems clean. You can use a mild soap and water to clean them. Avoid using harsh chemicals as they might damage the stickers. Also, be careful when washing your car not to rub too hard on the emblems. If you have any extra stickers, store them in a cool, dry place for future use.