Was lucky to get an X5 with M Sport Pack. and massive sport 20" X5 M Rims (Front: 20x10" / Back: 20x11"). As I had my test drive around the dealership I couldn't notice dramatic difference because they don't have access to hwy and at mid. speeds it may be confused with a typical road noise. However as I hit 45-55-65 miles the noise(that looks like come from front tires) becomes extremely loud. My mechanic and I agreed that this could only be bearing or tire related issue. The dealer confirmed that this is more likely "used" run flat tire issue. So, simple solution! Get new tires fix the noise! Done! Got myself brand new OEM: Bridgestone Dueler H/P Sport 275/40R20 106Y Tires, however the noise is still there. Not as loud (depending on speed about 70%-90% better than it was) but its still there. I already spoke with a number of people regarding this issue(including BMW service manager) and no one seems to know the solution to this problem. Online forums are full of topics with same noise issue that owners experience with sport 20" X5 M Rims, but still no clear answer. Changing all tires may be an excellent idea but what tires to buy? Tirerack has very poor choice of 315/35/R20 - 275/40R20 tire combos and those few tire sets that they have do not have positive feedback from owners. Even at $450 and over(single tire price) people still complain about same noise issues they experience. After spending few nights online and doing small research I came up with an interesting idea. Could it be a wheel geometry related issue? My front wheels have +40 Offset, Back: +35. If I would get equal offset rims, would it fix the problem? Any opinion on this would be greatly appreciated! P.S. attaching a pic of the wheels that I have.