2 out of 10 to get the bumper off. there are write ups on how to do it. I did not read them, just pulled all the plastic plugs on the top and bottom, and a few screws in the wheel wells I think. Just look around, you will figure it out.
My total xenon install took about 1.25 hours, with removal and re-install of the front bumper cover of my outback. Granted, it is high enough that I did not need to jack it off the ground, haha, but still, even with putting it on stands and removing the front wheels for the legacy, even a beginner would be less than 2 hours, at best guess.