Projector lights and aftermarket HID?

Sorry if this has been asked before, I did search, but couldn't find definitive answers.

My car is a 197 Sport on a 56 plate. It has projector dips, H7 main beam, and cornering lights. All are halogen at present.
I'd like to swap my dips and maybe also main beams for HID. Not bothered about the cornering lights.

First question: will an aftermarket HID burner PHYSICALLY fit inside the projector? I ask since a mate with projectors on a Golf found the bulb wouldn't go inside.

Second question: is it worth doing the main beams too? I've heard horror stories about HID bulbs in halogen reflectors causing scatter and not being as good as a decent halogen?

Lastly, where to buy? I want 4300K, or as close as possible, since I understand that the LOWER the colour temperature, the brighter in usable light output is the bulb, hence 4300K is OE? I'd also like reliable, I've heard of ballasts going in under a year......and I don't want to attract unwanted attention by going too blue.

TIA
 
I've done exactly what you have said above, with 4300k hids. It's easily possible, much easier if you take the headlights out completely, drill through the back of the headlight bulb cover, put bulb through and make sure plastic/rubber bung is seated properly to seal the light, and then I used super duper double sided tape to put the slim line ballast to the underneath of the headlight! Great light output and looks OEM
 
Does it need to be drilled? Won't the bulbs fit in the proper bulbholders already there?

And if you drill, how do you get the bulb correctly aligned?
 
I think the hole will be for the wires to run through as it won't use the OEM bulb plug etc. At least that's what I had to do when I fitted a kit to my dads Volvo V50.