People have projectors in their contour headlights? Never seen it.
Never Thats as close to a "How-to" as you'll get. Retrofitting takes alot of engineering, and trial and error as well as measurements.
You need to learn how to mount the projector level, how to mount it with the correct rotational cut off, and how to be able to aim them. Its ALOT of information, I researched alot, and am confident in some of my trial and error stages that I can set all of the above elements properly to have a fully functioning headlight / projector.
You need to start reading the forums over at HIDplanet, and read the automotive lighting FAQ. Once you've got a grasp over all of these things you can start
As for being able to mount a projector without cutting open the front of the headlights, its possible but would be difficult. I have some ideas on how it would be done, but none that Id like to share
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As for projector choice, Milan was a proponent of the hella 90mm projectors. He used them, Swazo used them, Dion used them, and maybe some others. They are a neat little unit, and as demonstrated by Dion (who really helped me with my swap) they are easy to mount and aim. They however do not look as good as True HID projectors do with HID systems. Goonz and myself prefer an actual HID projector. He used valeo's in his headlights, and I use Bosch projectors in mine. You should see some of the cut offs and color you can get from Hybrid projectors (RX330 projectors, and S2000 lenses
Good luck!