$2,000 installed, wow, that's pretty good, the BIXenon lights go for $1,600 each at the dealer + tax.
I don't know what lights they are, they had some group buy on an MB forum, mbklasse.com, that doesn't even exist anymore. The new ones were just ebay specials, had a name brand but who remembers but I can tell you, nobody sold them cheaper
The components, bulbs, ballasts, clips, wires, etc are probably made by one or two companies in China and there's probably a bunch of garage size companies assembling the components into kits in a sweatshop, working 18 hours a day under the most hazerdous conditions, swimming in toxic waste with child labor, at least that's what they show on Dateline.
You want to be safe, keep the old bulbs, if a HID goes out, you can unplug it anywhere and stick the old bulb in, no problem. Also, consider getting 2 kits, if a bulb goes out, throw out the whole side, ballast, bulb, clips and put in all new, heck, $40 a kit, that's as cheap as they were selling blue tinted halogens for a few years ago. Will it cause your car to burst into flames, maybe, happened to my parents MB while driving on the freeway on a sunny day in San Diego, no HID, no aftermarket stuff, just an MB doing it's thing. If it shorts out, you have fuses to protect you. Can disaster happen, yes, but the probability is very low and for that, we have insurance.