muffler and resonator

Where would be the best place to buy these for my 65 Barracuda Formula S. I just picked up the pipes from the manifold back for 200. Just need to add the remaining parts. I know Classic Industries have these, just thought there might be a place a little less expensive. Should I use the original muffler, or any suggestions from you who are using something else. Car has Commando engine and is stock.
Thanks