Don't buy a Dension or a VW iPod kit, my one lasted about 5 months.
Get a Connects2 one if possible, they're more robust. They'll control the iPod via the playlist function but won't show track names.
If you have a changer, it becomes redundant so what you can do is swap it with an VW armrest iPod "shelf" from eBay and sell the changer to make most of your money back. It takes 5 minutes to install too, no stereo removal required.