WCFAB 2006-2007 LBZ Duramax 4" Intake Kit with Air Box Stage 2Powdercoat colors can be found here! WCFab 2006 2007 GM LBZ 6. 6L Duramax Stage 2 Intake Kit with Air Box. This high flow, fabricated aluminum intake pipe and air box enclosure with dry filter assembly replaces the restrictive plastic factory parts on your diesel for improved engine performance. All new design significantly increases air flow to your turbo producing improved horsepower and torque, quicker throttle response, and cooler intake