You don't have to add the remote, and you could leave the shut off valve out but it would then always preheat the engine rather than just the cabin.
If you add the shut off valve you can add an adaptation to add another line to the MMI for Engine preheat ON/OFF.

That's good.

The remote side is like £200 or something if I remember correctly.

I would say remote is a must, or even better, Webasto Thermo Call which enables you to start it remotely by sending a SMS text message to it +++

http://www.ebay.co.uk/itm/WEBASTO-TH...item35d68b94e6

http://www.webasto.com/int/markets-p...s/thermo-call/

It would be very nice to have.

Get up, press the heat button so the car warms up while you're getting ready.

I love it.

SWMBO has it on her Nissan Leaf, it's pretty amazing :) Works in the summer too to cool it down.

I remember someone talking about a SMS activated relay to start the heater.
http://www.quantek.co.uk/GSM%20Remote%20Control.html

May be a cheaper alternative to the remote.

Mmmm all this heater talk has me thinking if it would be worth it on the S8

If you do the Aux heater coding on the MMI you get the timer options for Aux heater and Aux vent.
All the vent does is turn your blower on.
Which does help but I'm always paranoid of it draining the battery.
Solar sunroof needed.

It is worth it.
Group buy? +++

http://www.ebay.co.uk/itm/261633010631
I Think this is the pump, with the 90˚ inlet/outlet.

Looks right.
Different plug but that's not really an issue.