I can't speak to the diesel, but I bought a URO for my W210 gasser and it lasted something less than a year. I didn't realize it had failed, but the dealer noted it at a "courtesy inspection", so I bought the OE corteco, swapped it out and never looked back. By then the URO was more than a year old, so I tossed it in the garbage and didn't worry about the "warranty" on it.