My idea behind this is to give some basic info to people who do not know, or are unsure of what is available for the mustang exhaust market. Disclaimer: Exhaust is a very opinion oriented modification. I intend to be as unbiased as possible. Cams: "The bigger the cam, the more aggressive the idle will be." - belber095 This more aggressive sound happens because an aftermarket cam will increase the amount of time the valves are open. Making it sound different at idle. An extreme example of this is most true drag cars. They always sound rough when Idling. That sound is way more exaggerated than any street use cams will be, it is just the best example I could think of. Headers: Choices include: Unequal length shorties Equal length Shorties Longtube Headers take the exhaust gases directly from cylinders and "collect" them into the exhaust pipes. The stock headers are restricting, which slows exhaust flow from the engine. Aftermarket headers help to open up the exhaust flow. *Any more input from others would be greatly appreciated, I don't want to be giving false info" Mid Pipes On-Road Midpipes - These have catalytic converters, often required in states with emissions laws and checks. H-pipe X-pipe Off Road Midpipes - No catalytic converters. These are technically for use "on track only" use. H-Pipe X-pipe H-pipes and X-pipes are both used to equalize the exhaust flow through the pipes. Both will give you about the same horsepower gains. Generally speaking H-pipes are said to give you more low-end power, while X-pipes help more at higher RPM's. Sound wise an H-pipe will usually give a deeper, sound more of a rumble. The X-pipe is slightly higher pitched: more of a "exotic" sound. It is often described as more "raspy". But as I said the sound is all on basis of opinion. Also there is the option of Mac Prochamber Midpipe. It is a loose style of H-pipe. Instead of having just a pipe welded between the two sides it uses a box to achieve both good flow and good sound, while being less restricting. (Thank you white95) There is also the option of going true-duals Or not having a midpipe. This just means that the pipes are run straight from the headers back to the muffler without a crossover in between. Catback: Anything behind the Midpipe is often called the Catback. There are many different systems to choose from. The thing that changes in most all of them is the Muffler. The common types of mufflers are: Chambered (Flowmaster, Thrush, etc...) Straight Flow (Magnaflow, SLP, etc...) Glasspacks (Cherrybomb) "Turbo" (Most brands offer these, usually seen on cars with fewer than 8 cylinders) These are once again a preference of sound. Here are a couple of pictures to show the sound difference and power difference behind some of the more popular mufflers. Manufacturers like Cherry Bomb and others also have information on their websites that show the flow rates of their mufflers in cfm (cubic feet per minute). Such as this: After those components the muffler tips are also personal preference. You can dump your mufflers (has the pipes end right after the mufflers usually pointed down or out). You can also have your pipes run from the muffler out the back, or custom run out the sides (or however you can convince your muffler shop to run them really). From this point, I would like to invite everyone to submit video or sound clips of their exhaust set ups. Please include this info: Model: Such as Mustang (GT or v6), Thunderbird, etc... Engine: (4.6; 5.0; 3.8; etc...) Stock or aftermarket Cam: Your set up: Please include everything from headers back. If you still have stock headers please include that in your description. Thank you If you have anything you would like to be added, PM me and I will add it! I'm always open to more information.