Designed with sophisticated CAD modelling tools to ensure high flow and a perfect fit. With a range of diameters from 3 to 5.5 inches depending on the application, are replacing the OEM downpipes, Laser-cut brackets to fit onto the OEM-provided mounting points. Completely assembled and TIG welded with love from experienced hands. The Perfect Catalytic Converter/ Particulate filter bypass system to unleash Performance. Key Features of Mini Cooper S (R56) Catless Downpipe: Beautiful Racing Exhaust note Huge exhaust flow improvement Completely Bypass Primary and secondary Catalytic? Converters DPF & OPF* High Power/Torque Gains depending on mods Support power level proven over 1000 WHP Reduces back pressure on Turbo applications Built entirely in low carbon 304 Stainless Steel Mandrel-bent with laser-cut components Handmade Tig welded in House Bolt-on Plug and Play installation Compatible With BlackBoost and other Turbo Upgrades Not Street Legal. For race use only. Requires a tune.