Description Subaru KX21 4 stroke Gokart engine performance header pipe part number AS0284 Aussiespeed AS0287K long series 2 piece muffler includes 2 connecting springs to connect the header pipe to the muffler plus AS0310 rear bumper mounting kit to support the long series Aussiespeed muffler . This press bend header pipe suits subaru go kart engines & increases performance & torque for use on road type courses where rpm varies. The AussieSpeed Subaru go kart engine header pipe has a fully welded spring coupler for easy fitment of AussieSpeed AS0280P long muffler. This is a full exhaust system including muffler mount for Subaru ex17, ex19,ex21, ex27 & kx21.