AVO Legacy Twin Mufflers Sedan AVO S1B04M3HB001 AVO's Twin Muffler System for the BP/BL 2005+ Legacy GT sedan offers improved flow and a deep, smooth sound. The twin mufflers are constructed fully of stainless steel with 60mm (2 1/4") piping from the y-pipe. The 3" center gives a great sound out the rear with the AVO 4" tapered, round-rolled end tail pipe.