Hi, everyone here. I want to buy a MBP 15 inch these days. I like the specs of i7, but that's more expensive. So I have some questions please. 1. I use it for my university study and I play games occasionally (usually World of Warcraft). I'am wondering the difference of WoW performance between 15" i5 2.4GHz and i7. 2. Can I play WoW via Parallel Desktop on Windows 7? I know there's Mac version WoW, but I just want to know the performance of running WoW via parallels desktop. A big drop of FPS? or 4GB RAM insufficient? 3. Will 4GB be sufficient for my use? I don't really want to upgrade to 8GB on the official apple store, that's expensive. If I want to upgrade it by replacing a 2GB by a 4GB to increase the total RAM to 6GB, can I just buy one from amazon and replace it? That's all? Will there be some problems of compatibility? Will it work well? Thank you all in advance. Every useful replies would be very appreciated.