aux input
 

does anyone have an audio aux input in your car?
i would like to use mp3 player (like IPOD) in my car,
i know that if i use the cassette converter, the sound quality will dropped, however i don't know how about using aux input like in this website http://www.installer.com/aux/
basically it split up the input from Cd player, so please share some experinces, thanks