Hi. I want to buy an unlocked iPhone 4S, but it starts selling in the US only in November. Therefore, I was considering on buying the UK version of the phone, which I assume is unlocked since it costs 800 British Pounds, and additionally there is no "third step" in the British website, you just select the color and memory size (unlike the American site, in which you have a "third step", which is to select the carrier). Down to the point - Is there any difference between the US and UK versions of the phone? Talking about major software changes, I don't care if Siri says "Colour" instead of "Color". Thanks.