I have discovered a small crack in my center muffler. Another Maine winter is taking its toll. Initial estimates for repair from the dealership are ~$500.00 (muffler, clamps and labor). Are there any good aftermarket mufflers out there that bolt on the existing exhaust configuration? If I am going to drop $500 (or preferably less) I figure a modest performance modification might be at hand. Thoughts on options or should I stick with the original equipment?