Another option is with Garmin Nuvi
Here's my Garmin Nuvi 360 in my 2008 Eos Lux. The Nuvi 360 was about $400 new when I got it 2 yrs ago, but now about $200.00 so a great price. It does my navigation (Aquiring Satellite b/c it is in my garage at the time of the photo) but does a great job with nav. It also has a slot for an SD card and I've installed much music on that card. The Nuvi 360 works as an MP3 player. It is also Bluetooth with my mobile phone. Best part is the location of my install is out of the way on the windshield, low down so it doesn't attract too much attention. 12V power is right next to it. AND... running a mini-stereo plug from the headphone jack on the Nuvi and into the Armrest Aux in give me MP3s thru the Dynaudio (awesome) with touch screen control of my music. My Navigation is broadcast over the car audio also so even zipping along at 70mph I can hear the directions voiced to me with the top down. It is smart enough to pause the music when it needs to give directions. Using the bluetooth phone through the car audio helps me hear the person on the other end....they usually know I have the top down though b/c of the wind. Still great little gadget that does everything I wanted without paying a high price for a non-portable and harder to upgrade built in VW Nav system. By the way, no special mounting is needed. Using the "dash mount" that comes with the Nuvi, it slips down quite nicely into that little tray compartment and just neatly (looking at that photo, I could do a quick rearrange...) tuck the wires in. The Aux in cable is pretty well hidden next to the console too!