NGK Laser Iridium Evo 9 Stock Heat Spark Plugs Box of 4 (ILFR7H)

NGK is well-known for making reliable ignition components, and their Laser Iridium spark plugs are a great example of that. If you're working on your 2019 or 2020 Subaru WRX STI, these are the stock heat range plugs designed to keep your engine running smoothly. They're built to be a direct replacement for your original plugs, ensuring a proper fit and function.

What makes these plugs stand out is the iridium alloy used for the center electrode. This material has a very high melting point and is significantly harder than platinum, which means it holds up better over time and helps maintain a consistent spark. The pure alumina silicate ceramic insulator helps with heat transfer away from the plug, and the trivalent metal plating on the outside helps prevent corrosion and makes them easier to remove down the road. Most of these plugs also feature a platinum pad on the ground electrode, which helps them wear evenly, especially in modern ignition systems.

This set comes with four plugs, which is exactly what you'll need for your WRX STI. They're designed to provide a stable spark, which is crucial for efficient combustion and overall engine performance.