One problem related to manifold/header/muffler/tail pipe has been reported for the 2006 Subaru Forester. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2006 Subaru Forester based on all problems reported for the 2006 Forester.
Head gasket leak on the driver's side cylinder head of a 2006 Subaru Forester x. Mom's car (also a 2006 Subaru Forester x) has identical head gasket leak but on the passenger's side cylinder head. There is the possibility of oil dripping on the hot exhaust manifold. My car has had the head gaskets replaced under warranty. Her car is yet to be repaired.