I have a '92 3.9 V6 Dakota that I love like family. She is not fancy but when I press that skinny pedal she hauls all kind of butt. She used to get 20mpg and is now at 15. She has 192k on her. Problem is I am replacing my muffler every 2 years. I was told that my short travel distance to work of half a mile was the culprit as moisture did not have the time to evaporate. I now travel 19 miles one way mostly interstate. Am I getting the wrong muffler or what? I am getting what auto parts stores recommend. I know backpressure and all can make a difference. I don't want to be too loud, but do not like replacing often and do not want to harm engine. Do I need to go stainless, I live in SC so not like being in heavy snow.