I've said my opinion on this a few times... I see the body color painted bumpers on white X3s all the time and I think it looks pretty bad. Way too much white and then you have the black tires out of nowhere.

If the X5 was full body color I would've stayed away from white. Something like gray would probably work though. I personally like the white/black tone.

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'08 X5 3.0si - Alpine White / Saddle Brown interior
Specs: Sport Pkg, Premium Pkg, Tech Pkg, Comfort Access, Aero Kit, Style 433 staggered 20s on Conti DWS
Mods: Carbon 35 tint, LED angel eyes, GP Thunder 7500k fogs, H&R 20mm/25mm spacers, clear reflectors, gunsmoke-tinted taillights
Coded: Digital speedo, windows/sunroof/tailgate close via keyfob

X5 pics at Flickr