Significantly reduce turbo lag with our truly engineered downpipe. Designed for optimal performance and durability, our downpipe features full 304 Stainless Steel construction. Starting from the turbo, exhaust gasses enter our cast stainless steel bellmouth housing that utilizes internal shapes and features impossible to create with standard tubing. This design feature was chosen specifically to reduce turbo lag, improve low-end torque, and offer superior durability in high HP, high temperature uses. Another improvement realized is the reduction of exhaust noise entering the cabin common with the thin-walled tubing used in nearly all other downpipes on the market. From the cast bellmouth section the exhaust gasses smoothly flow through 3" mandrel bent stainless steel piping into a state-of-the-art metallic substrate catalytic converter. These metal substrate cats are designed for optimal durability and flow so well, they pose virtually no HP reduction on most street cars. The high-flow catalytic converter is included in the STREET version. The RACE version does not include any catalytic converter at all. This system replaces both the stock downpipe section and final catalytic converter section. They will mate up perfectly to the stock or any aftermarket cat-back system designed to attach to the factory donut style flex gasket. A bung necessary to use the second factory O2 sensor is included. In addition, an auxillary O2 sensor bung is located near the turbo in a position that's easy-to-reach from the engine compartment for wide-band O2 sensor use during tuning sessions. All flanges, hangers, O2 sensor bungs, casting and piping are constructed 100% from 304SS. TIG welding used exclusively.