Disclosed is a muffler (1, 21, 41) integrated with a catalytic converter bed (9, 32, 52) including a polymeric muffler body (2, 22, 42), an inlet pipe (3, 23, 43) in flow communication with engine exhaust, said inlet pipe connected to a first body mounting adapter (5, 25, 45) so as to hold the inlet pipe a heat insulating distance from said polymeric muffler body, said inlet pipe in flow communication with an inlet of said catalytic converter bed (9, 32, 52), and a perforated exhaust pipe (4, 34, 44) in flow communication with an outlet of the catalytic converter bed, said perforated exhaust pipe mounted on a second body mounting adapter (6, 26, 56) so as to hold the perforated exhaust pipe a heat insulating distance from the polymeric muffler body; said inlet pipe and said perforated exhaust pipe holding said catalytic converter bed a heat insulating distance from the polymeric muffler body, said first body mounting adapter, polymeric muffler body, and second body mounting adapter forming a sealed internal chamber to provide an insulating and noise abatement space (8, 28, 48).