Probable new owner 2012 3.5d - Tire advice?

We are very seriously looking at a 2012 3.5d and living in Germany, we have to run winter tires during, well the Winter.

So I am trying to get something on order and to decide what to do. I think I like black wheels with the Platinum Gray color, but haven't any idea what to do for tires, or if they even match what can be had in the US.

I am getting quotes for aftermarket 18" wheels and Hancook winter tires for around $1500+. Any gotcha's there?

My mechanic has a used set, silver 5-spoke 18's with Dunlop's on them for $550, but they are not the look I wanted and the wheels aren't in great shape. Tires are a little better than half.

Aside from that, any general advice about the 3.5l Diesel would be greatly appreciated. This is my first BMW, which makes me a greenhorn for sure!

Thanks!