Front Muffler

Disconnect the battery negative terminal.
Disconnect the rear oxygen sensor connector (A).

Fig 1: Identifying Rear Oxygen Sensor Connector
Courtesy of HYUNDAI MOTOR AMERICA
Remove the front muffler (A).
Tightening Torque:

39.2 ~ 58.8 N.m (4.0 ~ 6.0 kgf.m, 28.9 ~ 43.4 lb-ft)

Fig 2: Removing Front Muffler Bolts
Courtesy of HYUNDAI MOTOR AMERICA
Install in the reverse order of removal.
NOTE: When installing, replace with new gaskets.