88-17 HARLEY FLSTC: Magnaflow Rockstar 2-Into-1 Exhaust (BLACK) Set yourself apart from the crowd in Rockstar style. 2-into-1 performance meets the ultimate in custom style and performance gains you can feel. The Hi-Flow louver core muffler delivers upgraded dynamic horsepower gains over stock with untamed, deep, aggressive sound quality from idle to full throttle. The Rockstar features MagnaFlow's exclusive non-bluing, Magna-Black coated, 1-3/4" stainless steel head pipes. 12 mm and 18 mm O2 sensor ports allow for maximum tuning options.