2.5 L (Turbo) Model

RH side
1. Remove the collector cover and the engine side cover.
2. Disconnect the ground cable from battery.
  
  Fig 1: Disconnecting Ground Cable From Battery
  Courtesy of SUBARU OF AMERICA, INC.
3. Remove the air cleaner case. Refer to REMOVAL , Air Cleaner Case.
4. Disconnect the connector from ignition coil.
5. Remove the ignition coil.
  NOTE: Turn #3 ignition coil by 180 degrees to remove it.
  
  Fig 2: Locating Ignition Coil
  Courtesy of SUBARU OF AMERICA, INC.
6. Remove the spark plug with a spark plug socket.
7. Install in the reverse order of removal.
  Recommended spark plug: Refer to ELECTRICAL , LEGACY.
  
  Tightening torque (Spark plug): 21 N.m (2.1 kgf-m, 15.5 ft-lb)
  
  Tightening torque (Ignition coil): 16 N.m (1.6 kgf-m, 11.8 ft-lb)
LH side
1. Remove the collector cover and the engine side cover.
2. Remove the battery and battery carrier.
3. Remove the secondary air pump. Refer to REMOVAL , Secondary Air Pump.
4. Remove the bolts that attach the air pump duct to the rocker cover LH, and raise the air pump duct.
  
  Fig 3: Locating Air Pump Duct Bolts
  Courtesy of SUBARU OF AMERICA, INC.
5. Disconnect the connector from ignition coil.
6. Remove the ignition coil.
  NOTE: Turn #4 ignition coil by 180 degrees to remove it.
  
  Fig 4: Locating Ignition Coil
  Courtesy of SUBARU OF AMERICA, INC.
7. Remove the spark plug with a spark plug socket.
8. Install in the reverse order of removal.
  Tightening torque (Spark plug): 21 N.m (2.1 kgf-m, 15.5 ft-lb)
  
  Tightening torque (Ignition coil): 16 N.m (1.6 kgf-m, 11.8 ft-lb)
  
  Tightening torque (Air pump duct): 9 N.m (0.9 kgf-m, 6.6 ft-lb)