Using your Mishimoto aluminum radiator is easy. First, make sure your engine is cool before installation. Since it's a direct stock fit, you can simply remove the old radiator and replace it with the new one without any cutting or modification. Fill the radiator with the recommended coolant, and don't forget to attach the included 1.3 Bar High - Pressure Radiator Cap. When it comes to maintenance, regularly check the coolant level. If it's low, top it up with the appropriate coolant. Also, keep an eye on the radiator for any signs of leaks or damage. If you notice any issues, contact Mishimoto support as it's covered by the lifetime warranty. And remember, this radiator is sold individually, so you have everything you need in one package to keep your Subaru WRX running cool and smooth.