I'm no expert on this so someone else please chime in if I'm wrong. However, the power supply (setting) is the only difference that I know of between the computers in the US and in the UK. The same parts are available from the internet for both countries to my knowledge. From browsing these forums and putting together builds for other members... the few I have done... I never noticed anything on ebuyer.com and newegg.com that would alert me to think otherwise. However, I would wait for at least another comment as I'm not 100%.
Edit: And TP-Oreilly just confirmed before my post went through.