I for one would be interested in knowing more.... price, ease of fitment being the main questions! :-)
Very easy to fit on a GTV, you can hide the ballasts nicely under the plastic covers on either side of the engine bay, i actually sold one to an alfaowner member at the rolling road day at red dot, to fit on a gtv, we actually installed it there too, doesnt take long. Not sure what the members user name is i know his first name not sure if he would like me to mention his first name on this forum post - i'm sure he can comment if he likes the kit.
There are many cheap kits on ebay but you won't get aftersales support or a two year warranty.
I can supply for £100 a kit, if you order more than one kit then at £80.
Fitted one on my 147 selespeed works really well.
The two kits that i can recommend are the 6000k(blue/white) or the 4300k(which looks the same as regular bulbs but much brighter and whiter).
PM if interested and i can find out if my friend has it in stock.
I've had mine on the GTV for 18 months and still havent blown a bulb and i use them all the time for motorway driving.
I recommend getting your headlamps aligned after fitting as the HID bulbs are slightly longer making the beam level raise 1 cm, this is mainly so u dont blind other road users.
Replacement bulbs are £25
The H7R 4300k kit for 147 is brilliant as you dont have to adjust the beam level as the R stands for sheilded so the bulb itself has a shield on the top to stop it from glaring other drivers, but the 6000k H7 comes without the shield so its recommended you turn down the beam level just by 1 cm. This can be done urself.