Nice explanation by @ModBargains, and great recommendation to watch youtube clips.
Just to throw in my $.02. A catted x-pipe will make any aftermarket exhaust system louder. Make it an off-road, or catless x-pipe, and it will be louder than with cats. Be mindful of that when listening to youtube clips. You might love the sound, but hate the actual volume when installed on your car and you hear it in real-life.
The 5.0 can be VERY loud with just an axle-back exhaust. Mid-pipes take it to the next level. Personally, I love more noise, but its not for everyone. Have fun searching!