my 2007 sport came with the 20 inches....too tacky, too noisy on bad roads, so I changes to 19 Conti, very happy
in the winter I have 18
frankly, I don't see much difference in handling, braking, or other ....ing

its mostly in the looks

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j-p - montréal
2007 X5 4,8, saphire black, saddle brown, sport package SOLD
2011 X5 Diesel