Remus BMW M3/M4 Racing Resonated X Pipe Mid Section (F80/F82/F83)Remus BMW F80 M3 F82 M4 Racing Resonated X Pipe Mid Section replaces the factory front silencer for better airflow and a drastically improved exhaust note. Combine this X pipe with the Remus Axle Back Exhaust System for a full cat back. Why add a Remus Resonated X Pipe to your F8X? The X pipe replaces the restrictive OEM silencer which dramatically reduces back pressure. The X pipe also helps achieve that aggressive snarling sound the S55 is known