How do these plugs look to you? (image)

[Kenny Boxster]

Mike, when I took out my spark plugs they looked exactly the same, sans the fact they were BERU brand plugs. What thstone said can be very likely be a cause. If you can't find a leak you may want to check the radiators- it is very hard to diagnose unless you take the bumper/wheel well off. I had a small leak remedied by tightening a radiator clamp. Check the area where the coolant hose connects to the plastic radiator inlets and see if you can see any coolant around the area. What happens is that coolant leaks out slowly, but you will never see it, because it drips into the bumper/wheel well.