Arrow 71631MI Racing Collector Pipe for BMW S 1000 XR 15-19Arrow Exhaust Headers BMW S1000XR Not all exhaust pipes are made equal, the Arrow Exhaust Header bears all of Arrows experience accumulated from world class racing. That experience has lead Arrows to fine tune each part of their design and manufacturing processes. Everything from pipes diameters, sections bends, components, welding and layout are carefully tested to produce a product with high performance, reliability and last but not least, good