This Milltek system is designed to replace the factory particulate filter, providing a freer exhaust gas flow and improved engine response. It unleashes the vehicle’s true sound, adding a deep and aggressive exhaust tone. All components are made from aerospace-grade 304L stainless steel, ensuring resistance to corrosion and long-lasting durability even under harsh conditions. A perfect choice for those seeking enhanced performance and sound from their vehicle. Specifications - Pipe diameter (inches): 4.0 - Feature 1: With X Pipe to Milltek Axle Back Only - Feature 2: Requires Stage 2 ECU Remap or OPF/GPF Bypass Module - Feature 3: Does not require MSBM406 if installing with Milltek Downpipes