If they are true Xenon HID lights as they appear to be, there will probably be quite a bit involved in the installation. Even if the installation is easy, $1,600 is a very high price. If you will search you can find a thread with a link to a company in California that had upgrades for less than $1,000.
That said, I paid $1,000 extra when I bought a new 210 car in '96. I was not totally disappointed, but I wouldn't do it again. The problem is that the Xenon is LOW BEAM ONLY on all these lights. If they could give me Xenon on low AND high, I would be much more inclined to spend the money again. Having HID on low beam just doesn't help your vision very much.