5-Inch 400cpsi UHOX Catalytic Converter Downpipe

The Unitronic Performance Downpipe is engineered as a direct bolt-on upgrade for the MK8 Golf R® and 8Y S3® models equipped with the 2.0TSI EA888 EVO4 engine. Its primary function is to remove factory downpipe restrictions, thereby reducing turbo lag and improving the overall exhaust sound. This downpipe incorporates a high-output GESi 5” 400cpsi UHOX catalytic converter, developed in partnership with Unitronic. Constructed with TIG-welded stainless steel and featuring an OEM-style corrugated mesh flex bellow, it also includes CFD-optimized upper downpipe castings for superior flow efficiency into the large converter. The package includes necessary hardware like V-band clamps, centering rings, a stainless steel midpipe section, and an exhaust reducer, making it compatible with factory or upgraded cat-back exhaust systems. Installation is designed to be straightforward, with precise fitment achieved through 3D modeling technology, allowing for installation in a few hours by individuals with moderate mechanical skills. The difficulty level is rated as 4 out of 5. To achieve maximum performance gains, Unitronic Stage 2 ECU Software is required. When paired with this software and other supporting modifications, the downpipe can contribute to significant power increases, yielding up to 470HP / 431LB-FT.