A muffler assembly includes first and second muffler components that are each formed as a single piece. The first muffler component includes a first outlet pipe portion, a first bypass pipe mount portion, and a first resonator shell portion. The second muffler component includes a second output pipe portion, a second bypass pipe mount portion, and a second resonator shell portion. The first and second muffler components are positioned in an overlapping relationship such that respective portions are aligned with each other to form an outlet pipe, a bypass pipe mount, and a resonator shell. A noise attenuation valve assembly is also installed within the first and second muffler components. The bypass pipe mount is positioned at a non-perpendicular orientation relative to the outlet pipe such that a bypass pipe having a straight end mount can be received within the bypass pipe mount to bypass the noise attenuation valve assembly.