I am very disappointed with my former muffler, a Dynomax aluminumized turbo. My exhaust kept getting louder and louder so I replaced the complete system, figuring it is a bad glass pack. Wanting to save the Dynomax for future projects, I cut it off. A large chunk of rust came out of the pipe, it came out of the muffler. Found some holes in the tubes inside the muffler. Some rustproofing! The stock mufflers last longer. If I should ever replace my resonator again I would use a another brand of turbo or a stainless model. The noise will drive your batty after a few weeks of traffic.
