So, I was thinking, if you have two identical inside diameter pipes, one steel, one stainless steel, two high flow cats, and two equal size resonators at the exact same point in the exhaust system, and two identical straight through tube mufflers at the end, from a physical perspective, you have an identically performing exhaust. Depeding on where you go in terms of muffler shops, this could cost you from $300 installed where I go, to $600 installed where I used to go. Now assuming that you could find a good muffler shop like the first one, and if you didn't mind possibly replacing a section of rusted piping after a few years for less than $100 or so, then you'd be getting almost exactly the same performance and sound from the custom built system as from the manufactured system. I only say "almost exactly the same performance" because if you have welded bends as opposed to mandrel bends, you might lose a fraction of a horsepower due to the microscopic impedance to flow. Any comments?