I've been looking to add a usb connector/aux for the passengers in my car and have come across this for a cheap option:

Koolertron Car Digital Music Changer MP3 USB SD CDC: Amazon.co.uk: Car & Motorbike

Am I right in thinking that the symphony ii+ is the same as the symphony iii?

Next off I thought i'd see what my stereo is worth, I can only find one on ebay which is £325!! Are these really worth this much as you can pick the RNS up for 400 so I'd much rather go for that option! If so, would I need to upgrade anything like the can gateway? I know you did for the golfs but mines an 07 facelift so not sure.