Using this exhaust system is easy. First, make sure your vehicle is turned off and cooled down. Then, use the included hardware to bolt on the 3 - piece design following the factory OEM hanger rod construction. It should fit your 2015 - 2021 Subaru WRX or STI perfectly. For best results, have a professional mechanic install it if you're not experienced. When it comes to maintenance, regularly check the welds and connections for any signs of looseness or damage. Clean the exhaust tips with a mild stainless - steel cleaner to keep the burnt finish looking great. Avoid harsh chemicals as they may damage the stainless - steel material. Also, be careful when driving over rough terrain to prevent any impacts that could damage the exhaust.