I paid £400 for mine.....came from this bloke :
http://myworld.ebay.co.uk/dj.kolia/
THe 1st one I got had a broken rear Fakra connector....so sent it back and got another.....its worked faultlessly for the past 15 months. I hooked up a 6 disk CD changer and thats in the glovebox.......then fitted bluetooth module...(had to source the Bluetooth module from the german e-bay
www.ebay.de )
So Costs
RNS-e £400 (came with free wiring adapor. GPS antenna, 2006 Map DVD & code card)
CD Changer for Glovebox £30 - E-Bay bargain (not really needed as a 2GB SD card in the RNS-e will hold around 18 CD's worth of MP3 tracks)
CD Changer to RNS-e cable £18
207 Map DVD - free upgrade from main dealer
Bluetooth module (Q version) £140
Bluetooth Interface cable £35
Bluetooth Antenna £10
Bluetooth Microphone £60 from main dealer
OK...so for around £700 its all done and works great (still need a bit of VAG Com coding to sort out the phone book upload).....but its a great system....
Best of all though, when I sell my A4 I will either fit the whole lot in my new B7 A4 (my intended next purchase), or put the whole lot back on E-bay as a complete package.....should get a good price for it all....and refit the double DIN Symphony (which is in a box under the stairs) to my B6 A4.