HIDs are illegal on any car which don't have them from factory, to be legal your car requires headlight washers and a self leveling light sensor. Although this don't really bother many people, the thing with projector headlights is that the beam is not scattered, where as non projector headlights tend to throw the light all over the place and really don't benifit from having HIDs.. Also projector headlights tend to make HIDs look OEM thus being less likely to get pulled or fail an MOT.
As for bulbs I'd assume you require H7 fitment, but that's just a guess as I'm not 100% tbh.
Hope this helps some
Edit: also to add, pretty much all kits are plug an play these days, so they just plug into your existing bulb connection, and are a doddle to fit!