I did this the other day, but with a Kenwood headunit.
You need Connects 2 CTKVW01. Costs £60. It comes with:
-Fascia
-Radio cage to fit fascia
-Aerial adapter (this isnt great, but picks up main FM stations)
-Steering wheel control module (you need to tell whoever you buy it off what headunit you have so you get the correct fly lead)
Basically everythig you need to fit a double din headunit.