1999 E320 Wagon
If you get a head unit with mp3 capability then you don't need a changer. Alpine will release, later this year (don't ask me when), a head unit that will play mp3's burned onto a DVD (don't know about the dual layer DVD Rs). I saw a price somewhere and remember it to be less than $600 msrp. If that still doesent suffice take an alpine headunit and hook up an iPod to it.