on my 64 dart I went with the Hipo exhaust system. I got everything from Accurate ltd. I ended up using a Flowmaster instead of a turbo muffler. Has a great sound at idle and not loud.
I enjoyed my dealings with Accurate, good people. I bought the 2 1/2 inch stainless tips from them. They made very sure that I knew they were stainless and not chrome. That impressed the heck out of me.