Yesterday I went to a store to buy a Xbox. I looked in a store and there were like two different models for the same. There was xbox 360 arcade and Xbox 360 pro. The pricing was a bit different, too. The xbox 360 arcade was around $200 and the xbox 360 pro was $100 expensive that means $300. So I was wondering whats the difference between them. They look alike to me but the pro version is a lot expensive. What extra features does it have? Can a xbox 360 arcade later be upgraded?