The other alt. is have the flange cut off and have a floating flange put on the pipe and weld a flair section of pipe on the cut end. I try to use just Bosal exhaust, but lately I have no idea who is making the pipes I have been getting. If I didn't have an exhaust bender and mig welder I would be up the creek without a paddle most times. You can use Napp gas for your propane torch and it will get the thin stainless flange hot enough to bend with some pretty light blows to the Cat.. If you have a flat dolleyblock it will keep the flange straight as you tap on it. If not use a piece of 3/8 th steel plate big enough to cover the flange with a 1 or 2 inch overhange. I hope this helps. I feel the pain when wrong parts are made to work. Pauli