I have a Matrix muffler on my H22 Accord that I bought from www.summitracing.com and it sounds pretty decent. I left the resonators and had 2.25 piping from the cat. It sounded better when I first bought it, now it sounds like it is beginning to burn out or something. However, I was very pleased with it overall and it sounds deeper than many of the exhausts that I hear out on the road. Does every exhaust eventually begin to burn out or is it just the lower quality ones?