The Mishimoto racing thermostat for the 2001+ Subaru Impreza WRX/STI will promote greater cooling efficiency throughout your engine. The Mishimoto racing thermostat will significantly lower high engine temperature produced by modified and upgraded turbo applications.
This has reduced the engine temp when we are out and about on the trike and when I am towing our tear drop camper. The thermostat was a perfect fit in the engine block.