Oil coated spark plugs can cause more serious damage if not replaced in time. My 2005 Suzuki Forenza sedan had a worn rocker cover gasket. It's hard work, but better safe than sorry. It is good that the engine is a 4-cylinder. I like that the valve cover gasket came with the spark plug tube gaskets as they don't usually fit together anymore. Revain delivered it earlier than expected. 4 stars.