It's funny how people rely on satnav nowadays. Young uns theses days don't know where anywhere is. I was reading on another forum, these lads were arranging a meet in Northampton. One Lad from Milton Keynes hadn't got a clue where Northampton was, how to get there, or how long it would take.
I've managed without one for 25 years by just finding my way about the old fashioned way. If I'm going to somewhere I've never been before, I will do a dry run on google maps before I set out, dropping onto Street View at some tricky looking junctions, but that's all the technology I feel the need to use.
I would save your money and stick with the RCD510 and retro fit bluetooth. It's very, very easy to do. You will just need a hand with the coding, but that should cost you no more than a case of Stella to someone local to you with VAG-COM. The RCD510 is a great unit. As said earlier, plug in your ipod or USB stick in the armrest and off you go.