Need advice on phone/car infotainment system integration

Hey, Tribe. Hoping somebody here can help me.

I have an '08 VW R32 (US version) and the previous owner ordered it with the iPod interface to the music/GPS system (I know - yuck). I'm looking to replace the whole unit with something that integrates with my Lumia 920. Does anybody have experience with doing this? Does anybody know of any good audio vendors who have something I can use? I don't need GPS capability - the MAPS app on the Lumia is way better than anything car manufacturers can currently provide. Just audio and - if possible - phone call integration.

Thanks in advance.