Using the StopTech brake kit is straightforward. First, make sure your vehicle is parked on a flat surface and the engine is off. You can start by removing the old brake components from your 2008 Subaru WRX. Replace the old rotors with the provided StopTech slotted rotors, and install the new brake pads. Then, connect the stainless - steel brake lines carefully. When you're done, check all the connections to ensure they're tight. As for maintenance, regularly inspect the brake pads for wear. If they look thin, it's time to replace them. Keep an eye on the brake fluid level and make sure it's within the recommended range. Also, after driving in wet or muddy conditions, it's a good idea to clean the brakes to prevent rust and debris build - up. And always remember, if you're not confident in doing the installation or maintenance yourself, it's best to have a professional mechanic handle it.