Integrated Engineering Sport MufflerDIAL IT UP, TONE IT DOWN The iE Catback Exhaust transforms your MK8 GTI with a deep, aggressive attitude. For those craving more, pairing it with the iE ProCore Downpipe takes volume to extreme levelsgreat for track use but overwhelming for most on the street. This optional Sport Muffler strikes the perfect balance, adding more sound than the catback alone while toning down the full turboback setup to a street friendly level for everyday driving.