I bought this kit because I don't want the traditional flowmaster or glasspack sound, but the main reason is that I wanted to support an American company that supports the Mustang hobby. These parts are very well made and a lot of research went in to making them. I'd suggest springing for the concours kit. A lot of people told me that the square tubes don't change the sound, but I can't imagine how they won't. It seemed worth the extra bucks to get something unique and exactly like the original.