One problem related to manifold/header/muffler/tail pipe has been reported for the 2017 Subaru Forester. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2017 Subaru Forester based on all problems reported for the 2017 Forester.
Exhaust manifold cracked and needed replaced; was first advised that the catalyt converter was bad and would need replaced by a non Subaru service provider. When I took to Subaru dealer, was advised I had to pay for 2 hours labor to "diagnosis" the exhaust before they could advise of issue/fix; did not do at that time. Next Subaru maintenance requested to have situation diagnosed; was then advised that did not need to remove covers to diagnosis, they knew it was the exhaust manifold. Part was on backorder; ordered and then replaced; exhaust still loud and now have fumes that were not present prior to the repair.