I am getting a new batch of 55W HID kits next week. PM me if you want to get more details on them.
But to be safe, I would recommend getting the 55W. Like I mentioned before, I had problems with 35W xenons on LCI models. ECU didn't seem to like it.
There is no need of any other clips or adapters. Xenon bulbs can be inserted into OEM bulb holder, it just takes time until you get all the wiring and rubber grommet through that metal holder's hole.
Headlights need to be removed. Easier to work around the bulb socket.
Make sure ballasts are metal and heavy, not plastic ones. Metal dissipates heat better. Once they are installed, ballasts can be inserted and hidden into the hole just under the front wings and once the headlights are back in the car, ballasts will be hidden.
I wish you were in Dublin, I would look after you no problem