I've had a HID kit fitted for the last 4 years I think, its got to be the best mod/upgrade for the car as the stock bulb/projector combo is shocking IMO. Pretty much all HID kits are cheap Chinese tat, even form known sellers like Hids direct to all of ebay. All you need to know is even if they say no errors or cam bus compatible you'll need cancellers to make them work properly without errors. If I were you I'd get a set from HIDS Direct's ebay store, if they dont work complain untill they send out cancellers, if that fails feedback
. I will add if you have opcom then you dont need the cancellers as you can turn the HID/Zenon setting on with that.
Fitting is easy, where the male prong of your old bulb fits, you just replace it with a male spade connection. If you have light washers fitted they have to work with hids or you will fail your MOT, if you dont have any then your fine, they only fail if they are fitted and dont work.
In the link are the cancellers I mentioned, if you need them you need a pair.
http://www.hids-direct.co.uk/hid-decoders-obc-fix/