Using these COBB 1050x Fuel Injectors is easy. First, make sure your vehicle is one of the compatible Subaru models (WRX 2002 - 2014, STI 2007 - 2021, Legacy GT 2007 - 2012, or Forester XT 2006 - 2013). Then, add the injectors along with a fuel pump and get your car tuned. That's it, and you're good to go. When it comes to maintenance, keep an eye on the replaceable inlet filter. If it gets dirty, replace it to keep the injectors working well. Also, since these injectors are corrosion - resistant, they can handle different types of fuels, but it's still a good idea to use clean and proper fuel. During installation, as it requires an intermediate level of effort, if you're not confident, it's best to get a professional to do it. And always follow the tuning data provided with Accesstuner Software for the best performance.