Ah ok, so many to decide from :l where did you put the square box? I've seen people stick it under the light but I'm not so sure about that :s
There are a lot to choose from I agree! As Phil said, it would be best to get it from UK sellers, the eBay seller I got mine off was amazing! I ordered them Friday morning and received them the next day! I would highly recommend Metal based HID's. I found a great place for my ballast, I placed them on the top left and top right of the headlights there was 2 perfect sized places to put them, I didn't even need to bolt or stick them down.