aFe 48-36302 Mach Force XP 304 Stainless Steel Exhaust Down Pipe for BMW 335i L6-3.0L For N55 engines only Made of 304 stainless steel Down pipe produces 14 horsepower and a 39 pound-foot torque at 1900 revolutions per minute 100 percent TIG welded 1.5 inches resonatar