I left my 18's at an ex's house only to find out she sold them this summer when I went to pick them up. So now I am going to use 17's, as I never did my brake upgrade. IMHO minus sizing is better for snow traction for the 95% of X5's that are not 4.6 or 4.8. I considered buying tires for the type 87 20's but then I figured who the heck was going to buy those tires if I ever sold the car. So to make a long story short, I opted for a set of OEM 17's type 57. Tires for this are so cheap and easy to find 235/65/17. And since I have the fender flares I will need a spacer pair in the rear.