4.5" to 3.15" High-Flow Catted Downpipe

The CTS Turbo High-Flow Catted Downpipe is engineered to significantly improve exhaust flow and unleash the performance potential of your BMW B58 engine. Constructed from premium T304 stainless steel, the downpipe features robust hand TIG welding with back-purging, ensuring long-term reliability and performance. It measures 4.5 inches in diameter, tapering down to 3.15 inches (80mm) to ensure a perfect fitment with either the factory or an aftermarket exhaust system. The integrated high-flow 200-cell catalytic converter offers an improved flow rate over stock while still providing emissions control. The product is confirmed to fit both Rear-Wheel Drive (RWD) and xDrive all-wheel-drive models. A 12-month warranty is included, covering manufacturing defects. Please note that installing this downpipe may trigger a Check Engine Light (CEL). Proper tuning software is required to address this. Applications include the 2016-2019 BMW 340i, 440i, 540i, 740i, M140i, and M240i, all equipped with the B58 engine.