Using the HT Autos Bottom Line Kit on your 2004 - 2005 Subaru STI is a great way to enhance its look. First, gather all the parts from the box - you'll find a front splitter, side skirt extensions, and rear lips. Before starting the installation, make sure to clean the areas where the parts will be attached. While the kit comes with installation hardware, it's best to have a professional do the installation as some modifications might be required. After installation, the kit is easy to maintain. You can wash it with regular car wash soap and water. Just be gentle when cleaning to avoid any scratches. Also, avoid hitting the kit against hard objects as even though it's durable, it can still get damaged. If you notice any dents or chips over time, it's a good idea to have them fixed right away to keep your car looking its best.