To equate Kaehler products with factory MB products is a fallacy. I've personally seen Kaehler fuel pump relays for the 117 and 103 based cars fail in less than a year's time.

URO has been around for a few years now (that I know of). I have yet to see a URO product that is not a complete joke. They're not even worth giving the benefit of the doubt, considering there are far better alternatives out there.