I have twin 6" miter cut stacks on my 01, I also run a muffler and the noise is not bad even with both windows down. at idle and normal crusin' speed you hear the engine moe than the exhaust. Under heavy load or hard acceleration the exhaust can get pretty loud. I originally had no muffler but it was unbearable on long trips. A few headaches and a really upset fiance later, I put the muffler on er. I can still haul a cord of wood with ease, Even with my toolbox back there. Plywood, dimensional and rough cut lumber at 12' is no issue either. Only issue was stone, it was a pain to get all of it out, lol . Another bigger I ran into was plastic bags, I threw few bags back there and 40 minutes later when I got home I smelled burning plastic. Well the bags found the hot stacks and melted, lol. Mick