Buying a Sony Vaio Duo 11 or 13 in Japan

Hi guys,

I am currently in Japan and looking at purchasing a new Sony Duo Vaio 13. I am from the UK and the price here is significantly cheaper for much higher spec.

I was hoping maybe someone here had some experience of buying a laptop from a different country and could help me decide if it is a smart move or not.

The main problem is the language; I need to ensure that I can change the OS to English. Do I need to purchase Windows 8 Pro in order to do this?

The other things I need to check are:
- Warranty; will it be covered internationally
- Power; I need to check that the power supply will work on the different voltages

Is there anything else important you think that I need to consider about buying a laptop in a different coutnry?

Also, what do you guys think about the difference between the 13 and 11? The price hike is quite substantial, but would welcome opinions from people that own either machine.

Thanks alot!