After trying to get some kind of "official" BMW recommendations on winter tires from BMW NA (no luck whatsoever... ask your dealer was the reply) and several BMW dealers (answers ranging from call tire rack to whatever we have in stock, but we're not a tire dealer) I came across a pdf document on the BMW Canada website. Seems like they have their shit together. Wish I could say the same for BMW NA.

I'd like to upload it, but it's too large by 4kb. Any way someone can help me with this? I'd like to make it available to everyone.

The short point is that they officially recommend:

X3 - Double Spoke Wheels 112 18" with Dunlop SP Winter Sport winter tires

X5 - Star Spoke Wheels 74 18" with Pirelli Scorpion Ice & Snow winter tires

X5 (4.6is & 4.8is) - Spider Spoke Wheels 99 18" with Pirelli Scorpion Ic & Snow winter tires

X5 (2007+) - Star Spoke Wheels 209 18" with Dunlop Grandtrek WTM3 run-flat winter tires

Some interesting choices. Since Canada gets pretty decent snow I can only assume these recommendations actually mean something.