projectors are the solution... too often I see HID kits, like dan has mentioned, that are the wrong K rating... this just makes your eyes tired after driving and dazzles other people.
furthermore, when these HID kits (not all, mind you) are installed, often they aren't adjusted correctly and spray light everywhere, blinding everyone around you... more of a danger than anyone else.
like dan said, unfortunately you are trying to engineer reflectors that were never designed to take a HID globe and you'll get massive light flare...
but on your topic - if it's the right kit for your car, it should just be a case of replace the existing globes, and mount the ballasts somewhere safe, change the plugs over.... and hours work in it tops