Discover media (6.5")in older models

[fcbsoci]

I found this sat nav on eBay

http://m.ebay.co.uk/itm/VW-Golf-6-Passa ... nav=SEARCH

Is anybody here who knows what I exactly need to fit this model to my 2011 Passat cc ?

I currently have rns315 dab model with build in BT module.

I did some research and I know I can but lots of thing need to be change so Is this worth the money apart from unit price which goes down I see a bit.

Thanks in advance .