Congrats on the 440
Have you tried contacting your local dealers? I was able to get a winter rim and tire set for $1,800 about a month ago. They are OEM Style 441M Ferric Grey with 225/45/18 Pirelli Sottozero 2 Winter Run Flat tires.
They're more reasonably priced because the dealer told me they were take offs and that cars delivered in the winter come with these sets and then are swapped out to spec rims for delivery. The sets usually have delivery usage of 10-20 kms and when I was looking in the summer there were at least 3 sets available locally.
Please let me know if you want any more details and I can always pm a copy of invoice if that helps so someone can try to price match.