Shelf life W12

Good evening to you! Ask the experts and experts among you: How durable do you value the W12 in the 420 hp version from the GP0? How many kilometers can this unit create? How long does the transmission go with it? Are driving performances beyond 500,000 km realistic? I ask the question, since I am currently considering buying such a car after I have ruled out the V10 as an alternative because of the diesel problem with regard to environmental zones… Thank you and many greetings!