TmaxNikon won't honor what they are considered equipment "grey market" cameras or equipment. If you happen to purchase one of these, then the seller would provide any warranty service, if you're lucky. That being said, Nikon approved service centers should have no problems servicing your camera, at your own cost.
TmaxWarranty is a good question. Also Nikon USA has been known to refuse to service 'grey market' cameras, leaving you with a $430 paperweight if the camera ever develops a fault.