We are putting stainless steel turn down exhaust pipes on our Sanger. I'm not sure how much it will help, but we got them for a really good price so it's worth a try.
It probably would cost you more to have one made, unless you work in a machine shop where you might be able to get the materials for free, or discount. Oh yea you should probably be a great welder also. They are definetly worth the price.