The only way to make certain your 2003 Mercury Marauder will pass a California smog check with the engine modifications you've indicated is to make sure each modified component has an Executive Order number issued by the California Air Resources Board (ARB) indicating it is for street legal use in California; AND each modified component is specifically designed to be used as an engine modification for your 2003 Mercury Marauder.
We recommend contacting the manufacturer of these components and/or inspect the components owners manual for information pertaining to an EO number (sometimes referred to as a CARB number).
