Exhaust for my 07 audi a4?

Hey, im looking to buy an exhaust system for my audi a4 2.0 AWD turbo. I want a deep sounding exhause, not those annoying, loud obnoxious, dirt bike sounding exhausts. I want it to sound like http://www.youtube.com/watch?v=e8Qd9z8sFHU or http://www.youtube.com/watch?v=Eyu_hjwJ9eI, so I'm just wondering what you call these kind of exhausts? do deep sounding ones have a special name? Also, if u have a audi a4 with an exhaust system, and a video, be sure to link it. Any suggestions?