If you don't have bluetooth already - we discovered you need to wire in a bluetooth module, £200, and the microphone kit which goes into the cars fittings, and a couple of other bits.

in the end, i went for a Parrot MKI9200 from handtec.co.uk . Fairly easy to fit when you get the right SOT adapter lead (try ebay) but just a warning, you will have plugs that dont connect to anything!