KYOSTAR Catless Downpipes for BMW F97 X3 M & F98 X4 M S58 3.0T The KYOSTAR Catless Downpipes are designed for BMW F97 X3 M and F98 X4 M models equipped with the S58 3.0T Twin-Turbo Inline-6 engine. These high-flow downpipes replace the restrictive factory catalytic converter sections to improve exhaust flow efficiency, reduce exhaust restriction, and enhance turbocharger response for performance-oriented BMW M SUV applications. Featuring a catless dual downpipe design with