I'm in South Africa and ordered a headunit from the US as they weren't out here yet... not the first time I've done this, so besides for warantee issues, the only problem I've found is the US radio frequencies all end in a uneven number ie 88.1, 88.3, 88.5 where most of the radio stations in south africa end in an even number.
Never listen to the radio anyway, so doesn't bother me. If you do go ahead and purchase one, maybe make an image of your firmware in case something goes wrong in the future.