Our Intake Manifold Upgrade Kit enables your 1.8L naturally aspirated engine to produce more horsepower by delivering increased air flow. Precision tapered billet sleeve directly replaces restrictive mesh element in intake manifold. Provides improved low end punch and mid range pull through quick & easy installation. Includes detailed installation instructions. NOTE: Our testing has determined the stock ECU will compensate for the increased air flow provided by our Intake Manifold Upgrade Kit. Requires RIVA Power Filter Kit to meet U.S. Coast Guard certified flame arrestor