It's no secret that excess heat kills engines and chokes power. This is exactly why you need a Grimmspeed 160º thermostat for your high performance Subaru. The Grimmspeed thermostat will have a direct and dramatic effect on your engine, lowering operating temperatures in excess of 30º. OEM thermostats can actually seal closed if a failure occurs, leaving your engine even more susceptible to the Big Bada-Boom! The Grimmspeed thermostat is specially designed that if it does fail, it will lock open, flowing extra coolant into the block until the car can be safely shut down and repaired. Why take a chance? If you drive your Subie hard, you need a Grimmspeed 160º racing thermostat.