Allows the motor to run at the temp I want. Tim Zimmer is using it with great results.
The controller on it runs the fans (switches them on at 5* above the set temp), it also leaves the pump on after the car is off to help cool down the engine.

http://www.daviescraig.com.au/Elect..._Combo__12V____PART_No_8050-details.aspx

96 Talon TSI AWD - The Gold Digger/Never Ending Build