time consuming mostly. their projectors take a lot of the hassle out of doing the swap. the single hardest part is aiming them so that the beams are level, high enough, and even spread. took me like a week maybe to do mine, but i was only working on them a few hours a day. after that, another hard part is baking the headlights to split them apart, but that could have been because i used brand new headlights for my retrofit. if you have a dremel and patience, you can do it.
DJ, any close ups of your projos?