Mishimoto MMTS-WRX-15 Subaru WRX Racing Thermostat, 2015+ Direct fit for 2015+ WRX and 2014+ Forester XT Lower activation temp allows coolant to flow through the engine earlier Maintains lower temperatures and extends engine life Mishimoto Activation: 165.2F (74C) / OEM Activation: 190.4F (88C) Mishimoto Lifetime Warranty