It can be done William. Denis and I have done that sort of installation several times before. We can do the lot in half a day, along with loads of other retro-fits.
There are several components, as you surmised, to be bought and the D2B fibre optic network cable needs re-working with the addition of several D2B terminals in the network. The electrical wiring will already be in place, although sometimes well concealed. Have you got a CD changer in the boot? This is a common retro-fit done at the same time as the Voice, Bluetooth etc.
If you go ahead, do you intend to retro-fit yourself or will you bring your car to us? Denis (who breaks Jaguars) provides all the parts at considerably less than commercial breakers prices and we do the fitting, including any of the specialist SDD diagnostics that will be required, free of charge.
Alternatively, Denis can provide the parts by post for you to do the installation yourself.
Any help to you?