Originally Posted by X5 Meister

Go with whatever you like. I'm just saying that larger rims will invariably have lower profile tires.

Stock 17" rims have 65 profile tires, 18" - 55 , 19" - 45, 20" - 40, 21" - 35.

BMW says that high performance tires and low profile rims are more susceptible to damage. By definition, high performance tires are tires with a speed rating higher than H and sidewalls that are less than 50% of the thread width. Given those facts you can deduce that the 19" tires + rims will already be running a risk of damage, as I said in post # 13, and to be safe an 18" wheel+tire is a safer bet.