While I was in my local VW dealer earlier, picking my GTi up after having a new Cambelt and a service, I noticed a really smart Kenwood Multimedia Nav unit on display.
It was a DNX520VBT and is shaped the same as the OEM headunits.
Check it out here:
http://www.kenwood-electronics.co.uk/products/car/vw/DNX520VBT/Specs here:
http://www.kenwood-electronics.co.uk/car/vw/dnx520vbt_spec/It was £942.13 inc VAT for the unit, £995 inc fully fitted - if you wanted the iPod/iPhone cable this was £35 extra.
The guys were really helpful, gave me the leaflet and a print out about it and we had a good chat - they reckon it's better than the RNS-510 - the built in Garmin satnav Bluetooth and iPhone/USB connectivity with full control being the major benefits. It even works with the steering wheel controls!
Having played with my mate's RNS-510 I can confirm this Kenwood is probably just as good if not better.
There are a couple of things though - as far as I can tell the iPhone/iPod connector has to go in the front USB and aux sockets, which doesn't look great, and there was no mention of integration with the Computer display on the dashboard.
It is a lot cheaper than the factory option or buying a new RNS-510 from VW and not much more than buying a secondhand RNS-510 and having to buy a separate bluetooth unit.
I was trying to get the leaflet scanned in but I'm having technical issues with my old scanner which will only work with XP.
Oh, and surprisingly I can't find it anywhere cheaper online than at VW!