Fitment Information Honda Civic Si B16 (1999, 2000) *This header can only be installed on a B-series engine with a DOHC VTEC oil pan* Emissions Information This item does not replace, alter or remove any emissions equipment.  However, this item does not ship to California. Connects to the factory catalytic converter.     Specs & Features Requires a 2.5" Adapter flange (Not included) Yonaka Motorsports headers for all B-Series DOHC VTEC motors featuring 1 5/8" pipes with 2.5" collector flange. This is an aftermarket header, designed from the JDM 1998+ Integra Type R B18C engine. With the larger pipes and the larger 2.5" collector, it will immediately add horsepower. Totally redesigned to improve fitness and flow. This header is fully polished stainless steel. Purchase the optional donut gasket if you need one. It comes with the gasket at the header to the cylinder head connection.