if you have a performance shop near you go there and get the kits they sell. i always do this because stuff always goes wrong with hid kits, if its not the bulb its the ballast, if not that then wiring, etc, most performance shops have a warranty with their kits ranging from a month to a year. and its a lot easier to bring in the part that broke and get it replaced then dealing with mailing it out or waiting for new ones to arrive.
i live in wa and i get mine from VIP Performance in Portland OR, awesome customer service, they replaced my ballast and bulb because it was having problem. and extended my warranty another month just in case it breaks again. you will NEVER get that service online. seeing a seller face to face gives you the ability to explain your situation and have options.
thats just my 2 cents.