Bought this the other day and started to fit it this weekend.
This is the guide on the Vectra site I was using to get an idea on how to do it as its similar to the Astra: www.vvoc.com/forum/showthread.php?t=46827
There are only 2 wires to connect to get it to work but 2 more so it doesn't dim when you put the car in reverse or turn the interior light on. I will be doing the wiring in the week hopefully.
Here are a few pics of what I did the last few days.
This is all you need to cut off to fit it to the MK4 Coupe.
Trim trimmed so it fits the Coupe head lining nice.
Trim sprayed black.
And you can see how much deeper it is.
And this is it dimming and then slowly going back to normal.