Panamera Turbo (2017) vs. BMW M850 Gran Coupe

I’m about to make a decision either for an M850 GC or a Panamera Turbo (2017), both needed, with the M850 being 4 years younger and 30k km less on it. Price is not far apart now, but the Panamera is now older. I have to test both to be able to compare at least the driving feeling, but it’s also about other aspects. It seems to me to buy the M850 GC somehow “reasonable” because it’s actually younger. uch da a direct comparison by experience or general arguments for one of the vehicles? Thank you in advance. [Transferred from engine talk from the topic ‘Purchasing advice: M850 GC vs Panamera Turbo (2017)’.]