I do, did my mk6 golf mirror, satnav, folding mirrors and reversing camera.
Cool. I think this will be no problem for you. The auto-dimming mirror and factory non-dimming mirror must have the same mount on the windscreen surface (actually I've never seen a 8V with a different mount but the first time I asked a dealership if they could install an auto-dimming mirror in my A3 they said it was impossible, "you'll have to replace the windscreen", but it wasn't true of course).
You can buy the cable loom from Kufatec or other suppliers. I regret getting mine from a Chinese seller because when it was delivered I realized it had only two wires, when the genuine loom has 4 or 6, so I had to modify it in order to make it work with all functions. So, it's always a good idea to check if the loom is complete before buying. With 2 wires you can have a dimming mirror that works, but with 4 wires you can disable dimming when the car is in reverse and when dome lights are on. With 6 wires you can control exterior dimming mirrors if you plan to retrofit them in the future. It seems that the loom for Golf 7 is the same, but I'm not sure about connections or wire lenghts, maybe it's worth a check.
You may also make your own custom loom if you can't or won't to buy one. You will need a 8K0971833 type connector, with MCON 1.2 mm female terminals (corresponding VAG repair cable = 000979034E) that may be supplied with the connector housing. Of course, you'll need a crimping tool. Connector pinouts are:
1 - +VCC
2 - GND
3 - signal from reverse light (connect to wire on pin 11 of connector T73C on body control module J519)
4 - dimming signal to exterior mirrors (pin 2 on T27a door disconnector)
5 - dimming signal do exterior mirrors (pin 3 on T27a door disconnector)
6 - signal from roof light (pin 3 of 6 pin connector in the roof module)
The terminal to be added to the roof module 6 pin connetor is a MQS 0.63 mm female (corresponding repair cable = 000979009E). If you plan to install exterior dimming mirrors, the connector type is MCON 1.2 mm male (repair cable = 000979035E).
Pin 2 on the mirror connector is connected to ground. I've connected it to a GND in the roof module but your cable loom may be different. The +VCC is powered only when ignition is on (otherwise your mirror will stay on permanently with a green light and red button on). I've connected it to the original VCC point as defined in the fuse box list.
Hope this helps. Pleask ask in case I forgot something.
