One problem related to manifold/header/muffler/tail pipe has been reported for the 2008 Nissan Sentra. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2008 Nissan Sentra based on all problems reported for the 2008 Sentra.
The exhaust muffler flange failed. It was severely rusted, while the exhaust pipe and muffler were in great shape. The flange appears to be made of steel while the rest of the exhaust appears to be stainless steel and not affected by the winter weather in western NY state. The car was 5 months out of warranty.