Invidia Down Pipe "Australian Spec" w/300 CPSI CatNew for 2024: Revised design with 300CPSI catalytic converter to suit stricter EPA emissions requirements INVIDIA CATTED DOWN PIPE The most restrictive component of the factory exhaust system is the down pipe which begins right after the turbocharger. Invidia Exhausts use a open bellmouth design to completely open up the exhaust flow path out of the turbocharger. This open bellmouth design combined with a larger pipe diameter and smooth bends allows