Rodwst, that picture from 4-5-6 suggests a simple solution. Make a pipe out of pvc tubing in the shape you need then take that to a muffler shop with a tubing bender and have the pvc pipe duplicated in exhaust tubing of the correct diameter. If there is a metal supply store near you you could buy thicker wall tubing that would last longer. A tubing bender in good condition can bend 1/8" wall thickness tubing no sweat.
