Retro fitting sat nav?

Its not as simple with the unit in the link you posted, the RNS-D. This unit requires some rewiring which is different for CANBUS or non CANBUS cars. The later RNS-E unit is much easier to integrate. A simple plug and play harness available on ebay, a GPS aerial and nav DVD is all that is required.
 
That's great. Rns-e sat naval look newer as well....

I have sourced the wiring adapters on ebay which also have gps antenna etc...

All I need now is a rns e sat nav?

Anyone have one, what's the cost I should expect to pay for one?